Question

This is my question pls help

Answer 1

Answer:

a = 15

Step-by-step explanation:

Substitute b = 12 , a = 9 into the equation

12 = $\sqrt{a^2-9^2}$

12 = $\sqrt{a^2-81}$ ← square both sides

144 = a² - 81 ( add 81 to both sides )

225 = a² ( take square root of both sides )

± $\sqrt{225}$ = a , then

a = ± 15

a > 0 , so a = 15