A cone that is sliced through the vertex would make the shape of a triangle.
You are told the h eight is 10 cm and the radius is 4 cm.
The radius would be half the base, so the base would be 4 * 2 =8 cm.
The area of the triangle is found by multiplying the base by the height, then dividing by two.
Area = 8 x 10 = 80
80 / 2 = 40 square centimeters.
