SAT Math - How to find the length of the hypotenuse of a right triangle : Pythagorean Theorem

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In the figure above, is a square and is three times the length of . What is the area of ?

Explanation

Assigning the length of ED the value of x, the value of AE will be 3_x_. That makes the entire side AD equal to 4_x_. Since the figure is a square, all four sides will be equal to 4_x_. Also, since the figure is a square, then angle A of triangle ABE is a right angle. That gives triangle ABE sides of 3_x_, 4_x_ and 10. Using the Pythagorean theorem:

(3_x_)2 + (4_x_)2 = 102

9_x_2 + 16_x_2 = 100

25_x_2 = 100

_x_2 = 4

x = 2

With x = 2, each side of the square is 4_x_, or 8. The area of a square is length times width. In this case, that's 8 * 8, which is 64.

A right triangle has legs of 15m and 20m. What is the length of the hypotenuse?

30m

45m

35m

40m

25m

Explanation

The Pythagorean theorem is a2 + b2 = c2, where a and b are legs of the right triangle, and c is the hypotenuse.

(15)2 + (20)2 = c2 so c2 = 625. Take the square root to get c = 25m

In order to get to work, Jeff leaves home and drives 4 miles due north, then 3 miles due east, followed by 6 miles due north and, finally, 7 miles due east. What is the straight line distance from Jeff’s work to his home?

2√5

10√2

6√2

Explanation

Jeff drives a total of 10 miles north and 10 miles east. Using the Pythagorean theorem (a2+b2=c2), the direct route from Jeff’s home to his work can be calculated. 102+102=c2. 200=c2. √200=c. √100√2=c. 10√2=c

Two sides of a given triangle are both . If one angle of the triangle is a right angle, then what is the measure of the hypotenuse?

$5\sqrt{2}$

$2\sqrt{5}$

$7\sqrt{5}$

Explanation

If we know two sides are equal to and we know that one of the angles is a right angle, then that means that this must be a Special Right Triangle where the interior angles are $90$^{\circ}$, 45$^{\circ}$, 45$^{\circ}$$ .

With this special triangle, we also know that the measure of the hypotenuse is equal to the measure of one side of the triangle times the square root of that measure.

Since one leg of the triangle is . then the hypotenuse is equal to $5\sqrt{2}$ .

We could also solve this using the Pythagorean Theorem, like so:

$c^2=\sqrt{5^2+5^2}=\sqrt{50}=\sqrt{2\cdot25}=5\sqrt{2}$

What is the hypotenuse of a right triangle with side lengths and ?

Explanation

The Pythagorean Theorem states that . This question gives us the values of and , and asks us to solve for .

Take and and plug them into the equation as and :

$12^{2}+16^{2}=c^{2}$

Now we can start solving for :

$144+256=c^{2}$

$400=c^{2}$

$\sqrt{400}=\sqrt{c^{2}}$

The length of the hypotenuse is .

Trig_id

If and , how long is side ?

Not enough information to solve

Explanation

This problem is solved using the Pythagorean theorem $(a^{2}+b^{2}=c^{2})$ . In this formula and are the legs of the right triangle while is the hypotenuse.

Using the labels of our triangle we have:

$o^{2}+a^{2}=h^{2}$

$\dpi{100} h^{2}=(10ft)^{2} +(17ft)^{2}$

$h^{2}=100ft^{2}+289ft^{2}$

$h=\sqrt{389ft^{2}}$

$\rightarrow 19.7 ft$

Given the right triangle in the diagram, what is the length of the hypotenuse?

$10\ in$

$14\ in$

$12\ in$

$7\ in$

$20\ in$

Explanation

To find the length of the hypotenuse use the Pythagorean Theorem: $a^{2}+b^{2}=c^{2}$

Where and are the legs of the triangle, and is the hypotenuse.

$6^{2}+8^{2}=100$

$(100)^{\frac{1}2}=10$

The hypotenuse is 10 inches long.

To get from his house to the hardware store, Bob must drive 3 miles to the east and then 4 miles to the north. If Bob was able to drive along a straight line directly connecting his house to the store, how far would he have to travel then?

5 miles

25 miles

9 miles

15 miles

7 miles

Explanation

Since east and north directions are perpendicular, the possible routes Bob can take can be represented by a right triangle with sides a and b of length 3 miles and 5 miles, respectively. The hypotenuse c represents the straight line connecting his house to the store, and its length can be found using the Pythagorean theorem: _c_2 = 32+ 42 = 25. Since the square root of 25 is 5, the length of the hypotenuse is 5 miles.

In a right triangle, the lengths of the two smallest sides are 5 and 12. Find the length of the hypotenuse.

Explanation

In order to find the length of the hypotenuse, we need to use the pythagorean theorem, which states that

By substituting 5 for a and 12 for b, we get

or,

To solve for c we need to take the square root of 169, which is 13. Therefore, the hypotenuse is 13.

You leave on a road trip driving due North from Savannah, Georgia, at 8am. You drive for 5 hours at 60mph and then head due East for 2 hours at 50mph. After those 7 hours, how far are you Northeast from Savannah as the crow flies (in miles)?

$\sqrt{100000}$