Question

find the circumference and area of a circle of
1. radius 14 cm
2. radius 2.1. m
3. diameter 35 cm
4. diameter 77 cm​

Answer 1

Answer:

CIRCUMFERENCE OF CIRCLE =

2\pi \:r2πr

AREA OF CIRCLE =

\pi {r}^{2}πr

2

i) r = 14cm

CIRCUMFERENCE =2×22/7×14 = 88 cm

AREA= 22/7×14×14 = 616 cm ^2

ii) r =2.1m

CIRCUMFERENCE =2×22/7×2.1 = 13.2 m

AREA = 22/7×2.1×2.1= 13.86 m^2

iii) d= 35cm r = 35/2cm ( d=r/2)

CIRCUMFERENCE = 2×22/7×35/2= 110 cm

AREA= 22/7×35/2×35/2= 962.5 cm^2

iv) d=77cm, r= 77/2 cm

CIRCUMFERENCE = 2×22/7×77/2= 242 cm

AREA= 22/7× 77/2×77/2= 4685.5 cm^2

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Answer 2

Answer:

1)88 $cm^{2}$,616$cm^{2}$ 2)13.188$m^{2}$,13.86$m^{2}$ 3) 109.97$cm^{2}$,962.23$cm^{2}$ 4) 241.934$cm^{2}$,4657.22$cm^{2}$

Step-by-step explanation:

According to the information provide in the question it is given a

1) radius 14 cm

2. radius 2.1. m

3. diameter 35 cm

4. diameter 77 cm​

We  need  to find the circumference and area of circle

The circumference of a circle is defined as the linear distance around it. In other words, if a circle is opened to form a straight line,

Area of a circle is the region occupied by the circle in a two-dimensional plane.

Putting the formula

1) Radius =r = 14 cm

$Circumference = 2 \pi r\\C = 2\times \frac{22}{7}\times 14$

Converting to lowest term

$C= 2\times 22\times 2\\C =88cm^{2}$

Area = $\pi r^{2}$

Converting to the lowest term

$A =22\times 2\times 14\\A = 616cm^{2}$

2) Radius =r= 2.1 m

$C=13.188cm^{2}$

Area = $\pi r^{2}$

$A= \frac{22}{7} \times 2.1\times 2.1$

$A=13.86m^{2}$

3)

r=d/2

r=35/2 =17.5 cm

Converting to lowest term

$C= 2\times 3.142\times 17.5\\C=109.97cm^{2}$

Area = $\pi r^{2}$

$A= \frac{22}{7} \times 17.5\times 17.5$

Converting to the lowest term

$A =22\times 17.5\times 17.5\\A=962.23cm^{2}$

4)

r=d/2

r=77/2 =38.5 cm

$Circumference = 2 \pi r\\C = 2\times \frac{22}{7}\times 38.5$

$C =241.934 cm^{2}$

$A =\frac{22}{7} \times 38.5\times 38.5\\A=4657.22cm^{2}$