Find the curved surface area and total surface of a cone whose height is 28 cm and diameter is 42 cm.

Given, the diameter of the cone = 42 cm
∴Radius = 42 cm ÷ 2 = 21 cm, h = 28 cm 
slant height l = √(h² - r²) = √(28² - 21²) = 𢆧흉 = 7�m
Curved surface of cone = π rl 
                               = × 21 × 7𢆧 = 462�m²
∴Total surface area of cone = π r(l + r)
                             = × 21 × (7𢆧 + 21) 
                             = 462(𢆧 + 3)cm²