# What is the area of a circle that has a diameter of 4.2 cm?

Jul 31, 2018

Area of a circle

#### Explanation:

$A = \pi \times \frac{{D}^{2}}{4}$

D is the diameter

$A = 3.14 \times \frac{{4.2}^{2}}{4} = 13.85$ $c {m}^{2}$

Your answer is $13.85$ $c {m}^{2}$

Jul 31, 2018

Area of circle $A = 13.86$ $c {m}^{2}$

#### Explanation:

Area of circle $A = \pi {r}^{2}$

Radius (r) = Diameter (d) / 2

Given $r = \frac{d}{2} = \frac{4.2}{2} = 2.1 c m$

$A r e a = A = \pi {r}^{2} = \pi \cdot {2.1}^{2} = \left(\frac{22}{7}\right) \cdot {2.1}^{2} = 13.86 c {m}^{2}$