Question

find the slant height of a cone whose base diameter is 70cm and curved surface area is 4070cm²

Answer 1

csa=pi*r*l =4070
diameter=70
r=35

solving for l=37
height=√(37²-35²)=12

Answer 2

r=35 cm
csa is 4070cm2
therefore;
csa of cone = pi r L
4070 =22/7 * 70 * L
4070 = 22*10*L
407= 22L
L= 407\22
L=18.5cm