Question

use π=3.14 to find circumference of each circle. (a) Diameter=20 mm (b) Diameter=15cm​

Answer 1

Answer:

circumference=2πr

a)d=20mm

so radius=d/2=10mm

c=2×3.14×10

c=6.28×10

c=62.80mm Ans.

b)d=15 cm

so radius=d/2=7.5cm

c=2×3.14×7.5

=6.28×7.5

=47.1cm Ans.

Answer 2

Given - Diameter

Find - Circumference

Solution - Circumference is calculated by the formula: πd, where d is diameter.

Keep the values in formula to find the circumference.

a) Circumference = 3.14*20

Performing multiplication

Circumference = 62.8 mm

b) Circumference = 3.14*15

Performing multiplication

Circumference = 47.1 cm

So the circumference is first and second case is 62.8 mm and 47.1 cm respectively.