Find the length of a using the Pythagorean theorem

Answer:
a = 12
Step-by-step explanation:
a² + 9² = 15²
a² = 15² - 9²
a² = 225 - 81
a² = 144
take the square root of both sides
a = 12
Answer:
[tex] {a }^{2} + {9}^{2} = {15}^{2} \\ {a}^{2} = - 81 + 225 \\ {a}^{2} = 144 \\ a = \sqrt{144 \: } \\ a = 12[/tex]