Surface area is much easier then area in this case.
You would just find the area of each side, and since you know the slant height, if you were to take each side of the pyramid as a 2D figure, the base would be 6.4 inches as stated and the height 6.1, because if you look at where the slant height is and basically took a side as a 2D figure, it would be the same as the height.
Pretty sure most people know how to find the area of a triangle, but it's base * height / 2, or 6.4 * 6.1 / 2, or 19.52. Since there are four of these triangle side things, just multiply 19.52 by 4, to get 78.08.
There's still a square base, so just multiply 6.4 by itself to get 40.96.
Radius of cone is2.39cmor 2.4cm
volume of cone=45.19cm^3
Pi×r^2×h/3=45.19
22×r^2×7.5/7=45.19×3
r^2=45.19×3×7/22×7.5
r^2=948.99/165
r^2=5.7514545
r=2.39
Or we can say r=2.4cm
