Question

the slant height of an frustum of acone are 5cm and the perimeter of it's circular ends are 20cma and 12cm find the curved surface area of frustum​

Answer 1

Step-by-step explanation:

Slant height = l = 5 cm

Perimeter of 1st circular end (p1) = 20 cm

Perimeter of 2nd circular end (p2) = 12 cm

Therefore,

P1 = 2.π.r. ....(circumference)

20 = 2 × 3.14 × r1

therefore,

r1 = 10/3.14 = 3.18 cm

Similarly

P2 = 2.π.r.....(circumference)

12 = 2 × 3.14 × r2

r2 = 6/3.14 = 1.91 cm

Now, we know that,

CSA(Frustum) = π (r1 + r2) × L

==> 3.14 ( 3.18 + 1.91 ) × 5

==> 3.14 (5.09) × 5

==> 79.913 cm²

Therefore, the curved surface area of the Frustum = 79.913 cm²

IF you think I was right surely mark it as BRAINLIEST answer !!!