Geometry › Construct Inscribed Figures (Equilateral Triangles, Squares, Regular Hexagons)
Line is perpendicular to line
where both lines are the diameter of the circle. From this information triangle
must be a(n) _______ triangle.
obtuse triangle
acute triangle
equilateral triangle
right triangle
Line is perpendicular to line
and is 90 degrees. We know this because line
intercepts an arc of 180 degrees. An inscribed angle is half the measure of the intercepted arc. Therefore this must be a right triangle.
True or False: The inscribed angle theorem states that the inscribed angle is half the measure of the intercepted arc.
True
False
This is demonstrated by the inscribed angle on a circle. An inscribed angle is an angle whose vertex is on the circumference of the circle and whose sides extend as chords of the circle. This theorem is proven to be true and can be used to solve for angles of inscribed figures in circles. This theorem is portrayed in the figure below.
What are the steps to inscribe a hexagon in a circle?
1. Make a point at any point on the circle’s circumference
2. Draw an arc across the circle with a compass that is set to the length of the radius, this will be the next vertex
3. Draw arcs in this fashion until there are six vertices
4. Label every other vertex
5. Connect these three labeled vertices to create a triangle
6. Connect the unlabeled vertices to create a second triangle
1. Make a point at any point on the circle’s circumference
2. Draw an arc across the circle with a compass that is set to the length of the radius, this will be the next vertex
3. Draw arcs in this fashion until there are eight vertices
4. Connect any six vertices making six equal sides
1. Make a point at any point on the circle’s circumference
2. Draw an arc across the circle with a compass that is set to the length of the radius, this will be the next vertex
3. Draw arcs in this fashion until there are six vertices
4. These are the six vertices of the hexagon
5. Connect these six vertices making six equal sides
Explanation: The steps are shown below along with figures for more explanation
1. Make a point at any point on the circle’s circumference
2. Draw an arc across the circle with a compass that is set to the length of the radius, this will be the next vertex
3. Draw arcs in this fashion until there are six vertices
4. These are the six vertices of the hexagon
5. Connect these six vertices making three equal sides
Find the side lengths of the square inscribed in the triangle. The area of the entire triangle is 20.
Since we are finding the side lengths of a square, we really only need to find one side since all sides are congruent in a square. Recall that the formula for the area of a triangle is . We can find the area of the square by finding the area of the triangle and subtracting the area of the square. Having the area of the square will just be one of the side lengths squared, so if we take the square root of the area of the square, we will have our answer.
First, consider the small triangle in the upper corner. This is shown below:
The area of this triangle would be
We will consider the lower two triangles combined to be the second triangle:
The area of this triangle would be
And then we need to consider a third area which is the square
The area of the square would be
To get the total area of the triangle, we can sum all three areas.
We can sub in our areas and solve for to solve this problem
(multiply by 2 to get rid of fractions)
Find the area of the inscribed square in terms of where
is the radius of the circle.
Since is the radius, we can extend it to represent the diameter which is
.
We know that a square is made up of two right triangles. So the diagonal must be a product of the Pythagorean Theorem; . We should let
and since we are working with a square we know
. We can simplify this formula to be
If we take the square root of each side we get
The area of a square is just . So the area of this square in terms of
is
What are the steps to inscribing an equilateral triangle in a circle?
1. Make a point at any point on the circle’s circumference
2. Draw an arc across the circle with a compass that is set to double the length of the radius, this will be the next vertex
3. Draw arcs in this fashion until there are three vertices
4. Label every other vertex so that there are three vertices
5. Connect these three vertices making three equal sides
1. Make a point at any point on the circle’s circumference
2. Draw an arc across the circle with a compass that is set to the length of the radius, this will be the next vertex
3. Draw arcs in this fashion until there are six vertices
4. Label every other vertex so that there are three vertices
5. Connect these three vertices making three equal sides
1. Make a point at any point on the circle’s circumference
2. Draw a triangle with its three points on the circle’s circumference
Explanation: The steps are shown below along with figures for more explanation
1. Make a point at any point on the circle’s circumference
2. Draw an arc across the circle with a compass that is set to the length of the radius, this will be the next vertex
3. Draw arcs in this fashion until there are six vertices
4. Label every other vertex so that there are three vertices
5. Connect these three vertices making three equal sides
What are the steps to inscribing a square inside a circle?
1. Given a circle (or draw a circle) draw a line across the diameter
2. Draw a line perpendicular to the diameter that also bisects the diameter
3. Label all points that intersect the circumference of the circle
4. Connect the points on the outer edge of the circle to form the four sides of the square
1. Given a circle (or draw a circle) draw a line across the diameter
2. Draw a line parallel to the diameter
3. Label all points that intersect the circumference of the circle
4. Connect the points on the outer edge of the circle to form the four sides of the square
1. Given a circle (or draw a circle) draw a line across the diameter
2. Draw a line perpendicular to the diameter that also bisects the diameter
3. Create two triangles from these intersections
4. Combine the triangles to form a square
Explanation: The steps are shown below along with figures for more explanation
1. Given a circle (or draw a circle) draw a line across the diameter
2. Draw a line perpendicular to the diameter that also bisects the diameter
3. Label all points that intersect the circumference of the circle
4. Connect the points on the outer edge of the circle to form the four sides of the square
If a rectangle is inscribed in a circle what can be said about the relationship between the circles diameter and a measurement on the rectangle?
The diameter of the circle is equal to the diagonal of the rectangle.
The diameter of the circle is equal to the side length of the rectangle.
The diameter of the circle is equal to the side squared of the rectangle.
The diameter of the circle is equal to the perimeter of the rectangle.
All of the answers are equivalencies.
First understand what the term "inscribed" means.
"Inscribed" means to draw inside of. Therefore, a rectangle inscribed in a circle means the rectangle will be drawn inside of a circle.
From here the following image can be constructed.
The diameter of the circle is any and all straight lines that cut the circle in half. Since the rectangle is inscribed in that circle and all corners touch the circle then the diameter of the circle is equivalent to the length of the rectangle's diagonal.
Which of the following is the correct way to inscribe a square in a right triangle?
Bisect the right angle with a line that intersects with the hypotenuse, call this point A. Draw lines perpendicular to each leg of the right triangle that passes through point A, these are two sides of your square. The final two sides of the square are lines that run from the points intersecting the two legs down to the right angle vertex.
Bisect either of the acute angles with a line that intersects with the hypotenuse, call this point A. Draw lines perpendicular to each leg of the right triangle that passes through point A, these are two sides of your square. The final two sides of the square are lines that run from the points intersecting the two legs down to the right angle vertex.
Bisect either leg with a line that intersects with the hypotenuse, call this point A. Draw angle bisectors through each of the acute angles.
Find the center of the triangle. Draw a square around the center.
This becomes clear when demonstrated through a picture. Not only does this allow us to inscribe a square within a right triangle, but it also gives us the largest square possible within the right triangle.
How does one find the incenter of a triangle when trying to inscribe a circle within the triangle?
Pick any point within the triangle. Call this the incenter of the triangle.
Find the angle bisectors of any two angles of the triangle. Their intersection is the incenter.
Find the height of the triangle and draw the auxiliary line down to the base. The midpoint of this line is the incenter.
Find the bisectors of coming from any point of any two sides of the triangle. Their intersection is the incenter.
The incenter is the intersection of the triangle’s three angle bisectors. Drawing two of these angle bisectors is sufficient enough to find the incenter. Below is a figure that illustrates the incenter of a triangle as point A.