Question

Someone please help with this semi- circle question

Answer 1

Answer:

Hope this is correct.

4,047$cm^{2}$

Note: d.p. means decimal places

Step-by-step explanation:

The radius of the 1st circle is 12cm and the frame has 4cm. Remember that the radius can be drawn from the centre of the circle to any other point of the circumference.

Step 1 : Find the area of the 1st circle which is inside.

Area of a circle = 2π$r^{2}$

=2 x 3.142 x 12$cm^{2}$

=2 x 3.142 x 144cm

=6.284 x 904.896

=5,686$cm^{2}$ (nearest whole number)

Step 2: Add 12cm and 4cm = 16cm.

Step 3: Now find the area of the entire shape.

Area of a circle = 2π$r^{2}$

=2 × 3.142 × $16cm^{2}$

=2 × 3.142 × 256cm

=6.284 × 256cm

=1,609$cm^{2}$ (nearest whole number)

Step 4: Area of shaded region= 5,686$cm^{2}$ - 1,609

=4,047$cm^{2}$