Hello!
To find the volume of a square pyramid you use the equation
[tex]V = a^{2} \frac{h}{3} [/tex]
V is volume
a is a side length
h is height
Put in the values you know
[tex]V = 5^{2} * \frac{9}{3} [/tex]
Square the 5
[tex]V = 25 * \frac{9}{3} [/tex]
Divide the fraction
V = 25 * 3
The answer is 75 cubic inches
Hope this helps!