Question

Sara made a wax model of a rolling pin of diameter 10 cm. The rolling pin was shaped like a right circular cylinder with a right circular cone at each end as shown below. What was the total surface area of the rolling pin? Using complete sentences, describe the steps you used to calculate the surface area.

Answer 1

Calculate the surface area of the cones at each end. You will not need to be concerned with the base of the cone. The formula for SA would be SA=pi*r*s where r is radius at the base, and s is the slant height, pi as always is a constant. For the cone s=6. r=5 (cm)
Surface Area (SA)=30 pi sq cm double this for both ends so the ends are 60 pi or 188.5 sq cm. Before calculating the cylinder surface area, do you have any questions on the calculation of the surface area for the two conic ends?

Answer 2

find first the surface area of 2 triangles
second,find the area of a rectangle
Total Surface area = surface area of 2 triangles + surface area of a rectangle

Answer 3

this is a 3 dimensional solid. use formulas for solids.

Answer 4

For the cylinder, calculate the circumference and then multiply by it length.
=10*pi*14=439.8 sq cm now add the surface area of the cone ends getting total SA of
628.32 sq cm