Answer:
The height is 8cm
Step-by-step explanation:
Given
[tex]L_A = 240cm^2[/tex] --- lateral area
[tex]a = 12cm[/tex] --- base lengths
Required
The height of the pyramid
The lateral area of a square pyramid is:
[tex]L_A = a\sqrt{a^2 + 4h^2[/tex]
So, we have:
[tex]240 = 12\sqrt{12^2 + 4h^2[/tex]
[tex]240 = 12\sqrt{144 + 4h^2[/tex]
Divide both sides by 12
[tex]20 = \sqrt{144 + 4h^2[/tex]
Square both sides
[tex]400 = 144 + 4h^2[/tex]
Collect like terms
[tex]4h^2 = 400 - 144[/tex]
[tex]4h^2 = 256[/tex]
Divide by 4
[tex]h^2 = 64[/tex]
Take square roots
[tex]h = 8[/tex]
