Question

Find height of a cylinder whose radius is 7cm and t.s.a is 968cm

Answer 1

t.s.a of cylinder = 2 × pi × r ×h + 2× pi × r^2

968= 2 × 22/7 × 7 × h + 2 × 22/7 ×49

968= 44 × h + 308

968-308=44h

44h = 660

h = 660÷44

height of the cylinder is 15 cm

Answer 2

TSA of cylinder = 968 cm

${2πrh+2πr}^{2} = 968cm$

$(2 \times \frac{22}{7} \times 7 \times h) + (2 \times \frac{22}{7} \times 7 \times 7) = 968cm$

$44h + 308 = 968cm \\ 44h \: = 968 - 308 \\ 44h \: = 660 \\ h \: = \frac{660}{44} = 15 \\ h \: = 15 \: cm$