A cone has a radius of 20 cm and height 21 cm, then the total surface area (in cm$^2$)of the cone is:(Take $\pi = \frac{22}{7}$)
Answer & explanation
Correct answer: option 1
We know that,
Total surface area of cone = πr(l + r)
l2 = r2 + h2
We have,
Radius (r) = 20cm
height (h) = 21cm
l2 = 202 + 212
l = 29
Total surface area = \(\frac{22}{7}\) × 20 × (29 + 20) = 3080