Question

The total surface area of a cone having its slant height 9 dm and diameter of its base

as 24 dm is

(a) 792 sq dm (b) 729 sq dm (c) 279 sq dm (d) 297 sq.dm​

Answer 1

hello mate

Answer

Total surface are of cone having base radius r and slant height L is

( πr² ) + π × × L

Exp :-

r = 24 / 2 = 12dm

L = 9dm

=>

π ( 12 )² + π × 12 × 9

=>

π ×12 { 12 + 9 }

=>

π ×12 { 21 }

=>

( 22 / 7 ) × 12 × 21

=>

22 × 12 × 3

= 792dm²

792dm² = 792 / 10² m²

= 7.92m²