Question

A right triangle has a hypotenuse of 15 cm. What is the length for the missing leg if one of the two legs of the triangle is 5?

Answer 1

14.14 cm

Explanation:

using the Pythagorean theorem:

?² = 15² - 5² = 225 - 25 = 200

? = √200 = 14.14 cm

Answer 2

The other leg is 12 cm long.

Explanation:

c

2

=

a

2

+

b

2

,

where:

c

is the hypotenuse, and

a

and

b

are the other two sides (legs).

Let

a

=

9 cm

Rearrange the equation to isolate

b

2

. Plug in the values for

a

and

c

, and solve.

b

2

=

c

2

−

a

2

b

2

=

(

15 cm

)

2

−

(

9 cm

)

2

Simplify.

b

2

=

225 cm

2

−

81

cm

2

b

2

=

144 cm

2

Take the square root of both sides.

b

=

√

144 cm

2

Simplify.

b

=

12 cm