TACHS Math : Area of a circle

Example Questions

Example Question #1 : Geometry

Find the area of a circle with the following radius:

Explanation:

The area of a circle can be calculated using the following formula:

In this formula the radius is denoted by the variable, .

Substitute in the known variables and solve for the circle's area.

Example Question #1 : Geometry

Which is equal to the radius of a circle with area

Explanation:

The formula for the area  of a circle, given its radius , is . Replace with :

To find the radius , first, divide both sides by :

Now, find the square root of both sides. Since , 20 is the square root of 400, so

.

The radius of the given circle is 20.

Example Question #1 : Area Of A Circle

To determine whether a machine on an assembly line is filling bottles with the correct amount of soda, twenty bottles are selected. The tenth bottle and every tenth bottle after that are taken off the line and examined.

This is an example of which kind of sampling?

Systematic sampling

Stratified sampling

Cluster sampling

Convenience sampling

Systematic sampling

Explanation:

The sample in this scenario is selected from the population by choosing obects that occur at regular intervals. That makes this an example of systematic sampling.

Example Question #32 : Tachs: Math And Ability

What is the area of a circle that has a diameter of ?

Explanation:

Recall how to find the area of a circle:

To find the length of the radius, divide the diameter by two.

Now, plug it into the equation for the area of a circle.