IXL | Pythagorean theorem: find the missing leg length | 8th grade math

or

What is the length of the missing leg? If necessary, round to the nearest tenth.

b

=

meters

ref_doc_title.

or

Learn with an example

question

What is the length of the missing leg? If necessary, round to the nearest tenth.

a

=

kilometers

key idea

In a right triangle,

a

2

+

b

2

=

c

2

,

where

a

and

b

are the lengths of the legs and

c

is the length of the hypotenuse. This is called the Pythagorean theorem.

solution

Use the Pythagorean theorem, with

b

=

15

and

c

=

17

.

a

2

+

b

2

=

Pythagorean theorem

c

2

Pythagorean theorem

a

2

+

15

2

=

Plug in

b

=

15

and

c

=

17

17

2

Plug in

b

=

15

and

c

=

17

a

2

+

225

=

Square

289

Square

a

2

=

Subtract 225 from both sides

64

Subtract 225 from both sides

a

2

=

Take the square root of both sides

64

Take the square root of both sides

a

=

Simplify

8

Simplify

The length of the missing leg is 8 kilometers.

Looking for more? Try these:

Lesson: The Pythagorean theorem

or

$Confetti$

Excellent!

Now entering the Challenge Zone—are you ready?

Questions
answeredQuestions

0

Time
elapsedTime

hr	min	sec
00	00	04

SmartScore
out of 100
IXL's SmartScore is a dynamic measure of progress towards mastery, rather than a percentage grade. It tracks your skill level as you tackle progressively more difficult questions. Consistently answer questions correctly to reach excellence (90), or conquer the Challenge Zone to achieve mastery (100)! Learn more

0

Teacher tools

Work it out

Not feeling ready yet? These can help:

T.1Pythagorean theorem: find the length of the hypotenuse

AA.10Solve one-step equations with whole numbers

Lesson: The Pythagorean theorem