13.54 +2.063 +0.14 +52.1= 67.843
so the answer is D.

is asking for what number x will the function

will produce 81.
3x = 81
x = 27
The lateral area of the pyramid is 108.49 cm^2. The lateral surface area is the total of all of each side's area of a three-dimensional figure and it has a different method to calculate it. First, you must find the triangle's height by using the Pythagoras formula resulting 7.41 cm ( =squareroot(8^2-3^2)), thus, you can find the lateral area using the square and triangles area formula (108.49=(8*8) + 4*(0.5*3*7.41))<span>.</span>