Question

the total surface area of a cylinder is 8448 square cm . If the radius of its base is 28 cm , what is its height ?

Answer 1

Hi there !

Given,

Total surface area of the cylinder = 8448cm²

Radius of the base = 28cm

Let the height be ' h '

We know that ,

Total surface area of a cylinder = 2πr(h + r )

Substituting the known values, we have,

$8448 = 2 \times \frac{22}{7} \times 28(h + 28)$



$\frac{8448 \times 7}{2 \times 22} = 28(h + 28)$

$1344 = 28(h + 28)$

$\frac{1344}{28} = h + 28$

48 = h + 28

h = 48 - 28

h = 20

Thus,
the height of the cylinder is 20cm

Answer 2

Given,
TSA = 8448 cm²
Radius = 28 cm

Therefore ATP,
2 pie rh +2pie r²
or, 2r pie(h + r) = 8448
or, 2*28 pie (h+r) = 8448
or, (28*22)/7 *(h +28) = 4224
or, h + 28 = 4224/88 = 48
or, h = 48-28 = 20
So, height is 20 cm(Ans)......