Question

find the area of shaded region if the diameter of circle with centre o is 28cm and AQ=1/4AB

Answer 1

Answer:  463.5714 square cm (approx)

Step-by-step explanation:

Since, AQ=1/4AB

Thus, the diameter of small circle, AQ= 7 cm,

Also, the diameter of second small circle, QB = 21

Hence, the area of the shaded region = Area of the semi circle having diameter 7 cm + Area of the semi circle having diameter 21 cm,

= $\frac{1}{2}\times \pi \times (\frac{7}{2})^2+\frac{1}{2}\times \pi \times (\frac{21}{2})^2$

= $\frac{1}{2}\pi ( \frac{49}{4}+\frac{441}{4})$

= $\frac{1}{2}\pi(\frac{590}{2})$

= $\frac{1}{2}\times \frac{22}{7}\times 295$

= $\frac{6490}{14}$

= $463.571429\approx 463.5714$ square cm.