Question

4.The height of the cylinder whose radius is 7 cm and the total surface area is 968 square cm is .​

Answer 1

Step-by-step explanation:

15 cm is the height of the cylinder if the radius is 7 cm and total surface area is 968 .

Given:

Radius (r) = 7 cm

Total Surface Area =968

To find:

Height of the cylinder = ?

Solution:

The formula of total surface area of the cylinder is

Total surface area of the cylinder \bold{=2 \pi r(r+h)}=2πr(r+h)

From the given the total Surface area = 968.

Radius (r) = 7 cm

Substituting in the formula

Total surface area of the cylinder =2 \pi r(r+h)=2πr(r+h)

968=2×π×7(7+h)

h+7=

2×π×7

968

h+7=

2×

7

23

×7

968

h+7=

2×22

968

h+7=

44

968

h+7=221

h=15cm

The height of the cylinder is 15 cm.

Answer 2

2πr(r+h)=968

⇒2×

7

22

×7(7+h)=968

⇒7+h=

44

968

⇒7+h=22

⇒h=15cm