I really need help!!!

Lars stretched 12 yards of a string from stake X to stake Y and 9 yards of the string from stake Y to stake Z. The two strings meet at a right angle.

He wants to stretch the string from stake Z to stake X next. What is the distance from stake Z to stake X?

A.15 yards
B.21 yards
C.113 yards
D.3 yards

5 answers

The Pythagorean Theorem to the rescue!

a^2 + b^2 = c^2

12^2 + 9^2 = c^2

144 + 81 = 225

15 = c
hypotenuse
sqrt (12^2 + 9^2)

sqrt ( 144 + 81)

sqrt (225)

= 15
thank you so much!
i got a couple more qushtions can you stay and help me?
You are welcome.