Respuesta :

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

FatemehAlizadeh

Answer:

[tex] {a }^{2} + {9}^{2} = {15}^{2} \\ {a}^{2} = - 81 + 225 \\ {a}^{2} = 144 \\ a = \sqrt{144 \: } \\ a = 12[/tex]