Perimeter and Area of Plane Figures - Perimeter and Area of Composite Figures

Perimeter and Area of Plane Figures - Perimeter and Area of Composite Figures

The figure shows an ancient coin which was once used in China. The coin is in the shape of a circle of radius \(3\) cm with a square of sides \(x\) cm removed from its centre. The area of each face of the coin is \(7\pi\) cm\(^2\).

  1. Form an equation in \(x\) and show that it reduces to \(2\pi - x^2=0\).
  2. Solve the equation \(2\pi - x^2=0\).
  3. Find the perimeter of the square.

Video Solution:

Video Solution

Video solution locked

A free account saves your progress; this video needs a course plan.

Solution:

Solution locked

680+ questions here come with free worked solutions. A free account saves your questions and progress; this one needs a course plan.

Answer:(i) \(2\pi-x^2=0\). (ii) Algebraic roots \(x=\pm\sqrt{2\pi}\); the length is \(x=\sqrt{2\pi}\approx2.51\) cm. (iii) \(4\sqrt{2\pi}\approx10.0\) cm.

Need help? Join our A-Maths tuition classes.

Learn more