Question

The external radius and the length of a hollow wooden log are 16 cm and 13 cm respectively. If its thickness is 4 cm then find its T.S.A

Answer 1

External radius of the wooden log (R) = 16 cm

Thickness = 4 cm

Internal radius (r) = 16 – 4 = 12 cm

Length of the wooden log (h) = 13 cm

T.S.A of the hollow cylinder = 2π (R + r) (R – r + h) sq.cm

= `2 xx 22/7 xx (16 + 12)(16 - 12 + 13)  "sq.cm"`

= `2 xx 22/7 xx 28 xx 17  "sq.cm"`

= 2 × 22 × 4 × 17 sq.cm.

= 2992 sq.cm.

T.S.A of the hollow wooden = 2992 sq.cm