Question

Need help i don’t know what the answer is

Answer 1

r = 5

Explanation:

Using Pythagoras' identity in the right triangle ABC

AC² = BC² + AB²

(r + 8)² = r² + 12² ← expand left side using FOIL

r² + 16r + 64 = r² + 144 ( subtract r² from both sides )

16r + 64 = 144 ( subtract 64 from both sides )

16r = 80 ( divide both sides by 16 )

r = 5

Answer 2

r = 5

Explanation:

(r + 8)^2 = r^2 + 12^2

r^2 + 16r + 64 = r^2 + 144

16r = 80

r = 5