Question

Q15. A cone of radius 12 cm and height 5 cm is
mounted on a cylinder of radius 12 cm and height
19 cm. Find the total surface area of the figure
thus formed.
(a) 2498 cm2 (b) 2400 cm2 (c) 2476 cm² (d) 2376
cm2 (e) 2546 cm2.​

Answer 1

Answer:

tsa of figure so formed = 2376 square cm

option (d) is correct

Step-by-step explanation:

$r = 12 \: cm \\ h = 5 \: cm \\ slant \: height \: of \: cone \: = \: l = \sqrt{ {12}^{2} + {5}^{2} } \\ l = 13 \: cm \\ \\ tsa \: of \: cone \: = \: \pi(r)l \\ = \pi \times 12 \times 13 \\ = 156\pi \: {cm}^{2} \\ \\ \\ r2 = 12 \: cm \\ h2 = 19 \: cm \\ \\ tsa \: of \: cylinder \: = \: 2\pi(r2)(h 2) + \pi( {r2)}^{2} \\ = 2 \times \pi \times 12 \times 19 \: + \: \pi( {12)}^{2} \\ = (456\pi \: + \: 144\pi)\: {cm}^{2} \\ = 600\pi \: {cm}^{2} \\ \\ \\ therefore \: tsa \: of \: the \:figure \: thus \: formed \: = \: 156\pi + 600\pi \\ = 756\pi \\ = 756\times \frac{22}{7} \\ = 108 \times 22 \\ = 2376 \: {cm}^{2}$