Question

Find the circumference of the circle whose radius is: (a) 21 cm (b) 35 cm (c) 63 m (d) 49 m​

Answer 1

Answer:

a) 132 cm

b) 220 cm

c) 396 cm

d) 308 cm

Step-by-step explanation:

The formula for calculating the circumference of a circle is $2\pi r$.

Since the value of pi has not been defined in the question, we can take

$\pi= \frac{22}{7}$. The calculatins become much easier this way.

a) Circumference = $2\pi r$

                             = 2 × $\frac{22}{7}$ × 21 [Here, you can cancel 7 and 21, since 21 is a

                                                    multiple of 7.]

                             = 2 × 22 × 3

                             = 132 cm

b) Circumference = $2\pi r$

                             = 2 × $\frac{22}{7}$ × 35 [Here, you can cancel 7 and 35,  since 35 is

                                                   a multiple of 7.]

                             = 2 × 22 × 5

                             = 220 cm

c) Circumference = $2\pi r$

                             = 2 × $\frac{22}{7}$ × 63[Here, you can cancel 7 and 63, since 63  

                                                   is a multiple of 7.]

                             = 2 × 22 × 9

                             = 396 cm

d) Circumference = $2\pi r$

                             = 2 × $\frac{22}{7}$ × 49[Here, you can cancel 7 and 49,since 21 is a

                                                    multiple of 7.]

                             = 2 × 22 × 7

                             = 308 cm

Answer 2

Answer:

• Johnny by GGG high king via XML been CVCC CVCC bnnmkkk