PSAT Math : Right Triangles

Study concepts, example questions & explanations for PSAT Math

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Example Questions

Example Question #1 : How To Find The Length Of The Side Of A Right Triangle

A right triangle with a base of 12 and hypotenuse of 15 is shown below. Find x.

Screen_shot_2013-03-18_at_10.29.39_pm

Possible Answers:

5.5

5

4

3.5

4.5

Correct answer:

4

Explanation:

Using the Pythagorean Theorem, the height of the right triangle is found to be = √(〖15〗–〖12〗2) = 9, so x=9 – 5=4

Example Question #456 : Geometry

A right triangle has sides of 36 and 39(hypotenuse).  Find the length of the third side

Possible Answers:

33

15

42

12 √6

33√2

Correct answer:

15

Explanation:

use the pythagorean theorem:

a2 + b2 = c2  ; a and b are sides, c is the hypotenuse

a2 + 1296 = 1521

a2 = 225

a = 15

Example Question #81 : Triangles

Bob the Helicopter is at 30,000 ft. above sea level, and as viewed on a map his airport is 40,000 ft. away. If Bob travels in a straight line to his airport at 250 feet per second, how many minutes will it take him to arrive?

Possible Answers:

3 minutes and 20 seconds

1 hour and 45 minutes

3 minutes and 50 seconds

4 hours and 0 minutes

2 hours and 30 minutes

Correct answer:

3 minutes and 20 seconds

Explanation:

Draw a right triangle with a height of 30,000 ft. and a base of 40,000 ft. The hypotenuse, or distance travelled, is then 50,000ft using the Pythagorean Theorem. Then dividing distance by speed will give us time, which is 200 seconds, or 3 minutes and 20 seconds.

Example Question #81 : Right Triangles

A right triangle has two sides, 9 and x, and a hypotenuse of 15. What is x?

Possible Answers:

11

10

14

12

13

Correct answer:

12

Explanation:

We can use the Pythagorean Theorem to solve for x.

92 + x2 = 152

81 + x2 = 225

x2 = 144

x = 12

Example Question #82 : Triangles

The area of a right traingle is 42. One of the legs has a length of 12. What is the length of the other leg?

Possible Answers:

5

9

11

7

6

Correct answer:

7

Explanation:

Area= \frac{1}{2}\times base\times height

42=\frac{1}{2}\times base\times 12

42=6\times base

base=7

Example Question #11 : Right Triangles

Triangle

If  and , what is the length of ?

Possible Answers:

Correct answer:

Explanation:

AB is the leg adjacent to Angle A and BC is the leg opposite Angle A.

Since we have a  triangle, the opposites sides of those angles will be in the ratio .

Here, we know the side opposite the sixty degree angle. Thus, we can set that value equal to .

which also means

Example Question #83 : Triangles

Solve for x.

Possible Answers:

6

12

2

7

Correct answer:

6

Explanation:

Use the Pythagorean Theorem. Let a = 8 and = 10 (because it is the hypotenuse)

\small a^2+x^2=c^2

\small 8^2+x^2=10^2

\small 64+x^2=100

\small x^2=100-64=36

\small x=6

Example Question #462 : Geometry

Right_triangle

Note: Figure NOT drawn to scale.

Refer to the above diagram. Evaluate .

Possible Answers:

Correct answer:

Explanation:

The altitude perpendicular to the hypotenuse of a right triangle divides that triangle into two smaller triangles similar to each other and the large triangle. Therefore, the sides are in proportion. The hypotenuse of the triangle is equal to

Therefore, we can set up, and solve for  in, a proportion statement involving the shorter side and hypotenuse of the large triangle and the larger of the two smaller triangles:

Example Question #12 : Right Triangles

What is the hypotenuse of a right triangle with sides 5 and 8?

Possible Answers:

5√4

12

√89

15

8√13

Correct answer:

√89

Explanation:

Because this is a right triangle, we can use the Pythagorean Theorem which says a2 + b2 = c2, or the squares of the two sides of a right triangle must equal the square of the hypotenuse. Here we have a = 5 and b = 8.

a2 + b2 = c2

52 + 82 = c2

25 + 64 = c2

89 = c2

c = √89

Example Question #1 : How To Find The Length Of The Hypotenuse Of A Right Triangle : Pythagorean Theorem

Trig_id

If  and , how long is side ?

Possible Answers:

Not enough information to solve

Correct answer:

Explanation:

This problem is solved using the Pythagorean theorem  .  In this formula  and  are the legs of the right triangle while  is the hypotenuse.

Using the labels of our triangle we have:

 

 

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