Common Core: 8th Grade Math : Apply the Pythagorean Theorem to Determine Unknown Side Lengths in Right Triangles: CCSS.Math.Content.8.G.B.7

Study concepts, example questions & explanations for Common Core: 8th Grade Math

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Example Questions

Example Question #62 : Plane Geometry

The legs of a right triangle are equal to 4 and 5. What is the length of the hypotenuse?

Possible Answers:

Correct answer:

Explanation:

If the legs of a right triangle are 4 and 5, to find the hypotenuse, the following equation must be used to find the hypotenuse, in which c is equal to the hypotenuse:

Example Question #53 : Triangles

Righttriangle

Triangle ABC is a right triangle. If the length of side A = 3 inches and C = 5 inches, what is the length of side B?  

Possible Answers:

6 inches

1 inches

1/2 inches

4.5 inches

4 inches

Correct answer:

4 inches

Explanation:

Using the Pythagorean Theorem, we know that .

This gives: 

Subtracting 9 from both sides of the equation gives: 

 inches

 

Righttriangle

Example Question #82 : Geometry

An 8-foot-tall tree is perpendicular to the ground and casts a 6-foot shadow. What is the distance, to the nearest foot, from the top of the tree to the end of the shadow? 

Possible Answers:

\dpi{100} \small 4

\dpi{100} \small 6

\dpi{100} \small 5

\dpi{100} \small 10

\dpi{100} \small 8

Correct answer:

\dpi{100} \small 10

Explanation:

In order to find the distance from the top of the tree to the end of the shadow, draw a right triangle with the height(tree) labeled as 8 and base(shadow) labeled as 6: 

 Screen_shot_2013-08-16_at_12.34.40_am

From this diagram, you can see that the distance being asked for is the hypotenuse. From here, you can either use the Pythagorean Theorem:

\dpi{100} \small a^{2}+b^{2}=c^{2} 

or you can notice that this is simililar to a 3-4-5 triangle. Since the lengths are just increased by a factor of 2, the hypotenuse that is normally 5 would be 10. 

Example Question #62 : Triangles

Figure6

Find the perimeter of the polygon.

Possible Answers:

Correct answer:

Explanation:

Divide the shape into a rectangle and a right triangle as indicated below.

Figure7

Find the hypotenuse of the right triangle with the Pythagorean Theorem, , where  and  are the legs of the triangle and  is its hypotenuse. 

This is our missing length.

Now add the sides of the polygon together to find the perimeter:

Example Question #52 : How To Find The Length Of The Hypotenuse Of A Right Triangle : Pythagorean Theorem

Find the length of the hypotenuse of the following right triangle.

1

Possible Answers:

Correct answer:

Explanation:

Recall the Pythagorean Theorem, which is used to find the length of the hypotenuse.

For any triangle with leg lengths of  and ,

13

Take the square root of both sides to find the length of the hypotenuse.

Plug in the given values to find the length of the hypotenuse.

Example Question #11 : Apply The Pythagorean Theorem To Determine Unknown Side Lengths In Right Triangles: Ccss.Math.Content.8.G.B.7

Find the length of the hypotenuse of the following right triangle.

2

Possible Answers:

Correct answer:

Explanation:

Recall the Pythagorean Theorem, which is used to find the length of the hypotenuse.

For any triangle with leg lengths of  and ,

13

Take the square root of both sides to find the length of the hypotenuse.

Plug in the given values to find the length of the hypotenuse.

Example Question #284 : Triangles

Find the length of the hypotenuse of the following right triangle.

3

Possible Answers:

Correct answer:

Explanation:

Recall the Pythagorean Theorem, which is used to find the length of the hypotenuse.

For any triangle with leg lengths of  and ,

13

Take the square root of both sides to find the length of the hypotenuse.

Plug in the given values to find the length of the hypotenuse.

Example Question #12 : Apply The Pythagorean Theorem To Determine Unknown Side Lengths In Right Triangles: Ccss.Math.Content.8.G.B.7

Find the length of the hypotenuse of the following right triangle.

4

Possible Answers:

Correct answer:

Explanation:

Recall the Pythagorean Theorem, which is used to find the length of the hypotenuse.

For any triangle with leg lengths of  and ,

13

Take the square root of both sides to find the length of the hypotenuse.

Plug in the given values to find the length of the hypotenuse.

Example Question #425 : Grade 8

Find the length of the hypotenuse of the following right triangle.

5

Possible Answers:

Correct answer:

Explanation:

Recall the Pythagorean Theorem, which is used to find the length of the hypotenuse.

For any triangle with leg lengths of  and ,

13

Take the square root of both sides to find the length of the hypotenuse.

Plug in the given values to find the length of the hypotenuse.

Example Question #431 : Grade 8

Find the length of the hypotenuse of the following right triangle.

6

Possible Answers:

Correct answer:

Explanation:

Recall the Pythagorean Theorem, which is used to find the length of the hypotenuse.

For any triangle with leg lengths of  and ,

13

Take the square root of both sides to find the length of the hypotenuse.

Plug in the given values to find the length of the hypotenuse.

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