Question

The surface area of three dimonsensed face is the sum of all the the surface areas of each of the face given below are the nets of some solid derive the formula for calculating its curved surface area and total surface area

Please answer the question it's very urgent​

Answer 1

cylinder:

curved sa = 2πrh

=> rectangle, breath = h, width = perimeter of circle = 2πr

total sa = 2πrh+2πr^2

=> curved sa + area of 2 circles

cone:

curved sa = πrl

=> treated as a triangle, base = circumference of circle, height = slant height

total sa = πr^2+πrl

=> curved sa + area of base (circle)