I need help please and thank you

Answer:
12
Step-by-step explanation:
Pythagorean Theorem states that a^2 + b^2 = c^2. Using the numbers that you're given you should have an equation of a^2 + 9^2 = 15^2.
Once you square your terms you should have a^2 + 81 = 225
You can find a^2 by subracting b^2 from c^2. So 225 - 81 = 144
Then you find the square root of 144, which is 12.
Answer:
a = 12
Step-by-step explanation:
The Pythagorean Theorem is: [tex]a^{2} + b^{2} = c^{2}[/tex]
So, let's input the values we know and solve for a.
b = 9 c = 15
[tex]a^{2}[/tex] + [tex]9^{2} = 15^{2}[/tex]
[tex]a^{2} + 81 = 225[/tex]
Subtract 81 from both sides to isolate the a: [tex]a^{2}[/tex] = 144
Find the square root of both sides to isolate the a: a = 12
The length of a is 12.