Given:
slant height of the frustum = 9 ft
radii of the bases = 5 ft and 7 ft
Find:
Lateral Area and Total Area (I assume this is surface area.) of the right circular cone.
Solution:
(Let [tex] \pi [/tex] be 3.14.)
Lateral Area = [tex] \pi [/tex](R + r)s
= 3.14( 7 ft + 5 ft) 9ft
= 3.14 ( 12 ft) 9ft
= 3.14 ( 108 ft²)
= 339.12 ft²
Surface Area = [tex] \pi [/tex] [s (R + r) + R² + r² ]
= 3.14 [ 9 ( 7 + 5 ) + 7² + 5² ]
= 3.14 [ 9 ( 12 ) + 49 + 25 ]
= 3.14 [ 108 + 74 ]
= 3.14 [ 182 ]
= 571. 48 ft²
