Question

2. Taking pi = 22/7 find the area of the circle whose diameter is
(a) 28 cm
(b) 560 mm
(c) 8.4 cm​
(d) 2.1 m

Answer 1

Step-by-step explanation:

π = $\frac{22}{7}$

1. d = 28cm ⇒ r = $\frac{28}{2}$cm = 14cm.

Ar. = πr² = $\frac{22}{7}$×14cm×14cm = 616cm²

2. d = 560mm ⇒ r =$\frac{560}{2}$mm = 280mm = 2.8cm

Ar. = πr² = $\frac{22}{7}$×2.8cm×2.8cm = 24.64cm²

3. d = 8.4cm ⇒ r = $\frac{8.4}{2}$cm = 4.2cm.

Ar. = πr² = $\frac{22}{7}$×4.2cm×4.2cm = 55.44cm²

4. d= 2.1cm ⇒ r = $\frac{2.1}{2}$cm. Ar. = πr² = $\frac{22}{7}$× $\frac{2.1}{2}$cm× $\frac{2.1}{2}$cm = 3.465cm²