find the height of radius is 21 cm and volume is 13860 cm cube
Answers
Answer:
1. Find the curved surface area and total surface area of a cylinder, the diameter of whose base is 7 cm and height is 60 cm.
Solution:
We have,
Diameter of cylinder = 7 cm
So, Radius of cylinder = 7/2 cm
Height of cylinder = 60 cm
By using the formula,
Curved surface area of cylinder = 2πrh
= 2 × 22/7 × 7/2 × 60
= 1320 cm2
Total surface area of cylinder = 2πr (h+r)
= 2 × 22/7 × 7/2 (60 + 7/2)
= 22 (127/2)
= 1397 cm2
2. The curved surface area of a cylindrical road is 132 cm2. Find its length if the radius is 0.35 cm.
Solution:
We have,
Curved surface area of cylindrical road =132 cm2
Radius of road = 0.35 cm
Let length of road be ‘h’ cm
By using the formula,
Curved surface area of cylindrical road = 2πrh
So, 2πrh = 132
2 × 22/7 × 0.35 × h = 132
h = 132×7 / 2×22×0.35
= 924 / 15.4
= 60cm
∴ Length of road is 60 cm.
3. The area of the base of a right circular cylinder is 616 cm2 and its height is 2.5 cm. Find the curved surface area of the cylinder.
Solution:
We have,
Area of base of right circular cylinder = 616 cm2
Height of cylinder = 2.5 cm
Let the radius of cylinder be ‘r’ cm
By using the formula,
Area of base of right circular cylinder = πr2
So, πr2 = 616
22/7 r2 = 616
r2 = 616×7 / 22
= 196
r = √196
= 14cm
∴ Curved surface area of cylinder = 2πrh
= 2 × 22/7 × 14 × 2.5
= 1540/7
= 220 cm2
Step-by-step explanation:
Answer:
The radius of the base of a right circular cylinder is 5 cm and height is 21 cm.
Here, r=5 cm and h=21 cm.
Curved surface area of cylinder =2πrh
=2×
7
22
×5×21
=44×15
=660 cm
2
∴ The curved surface area of cylinder is 660 cm
2
.