The answer would be b.100 because its clearly not a right triangle
3.73 rounded to the nearest whole number would be 4
Recall that the volume of a regular prism is given by the area of the base times the height.
Given that the base of the prism is a regular pentagon with an apothem of 2.8 centimeters.
The pentagon consist of 5 isosceles triangles with the apothem as the height and the side of the pentagon as the base.
Recall that the are of a triangle is given by 1/2 base times height.
Thus the area of of the pentagon base of the prism is given by

Therefore, the volume of the prism is given by
Using a calculator: cos 70 deg = 0.342. Note: it sounds as tho' you were given several answer options. Where are they?