
A composite figure is presented, comprising a rectangle and an isosceles triangle.
Step 1: Construct perpendicular $DE$ from point $D$ to line $AB$.
This segmentation yields:
Step 2: Compute the area of the rectangle.
$\text{Area of rectangle} = \text{length} \times \text{breadth} = 5 \times 4 = 20 \;\text{cm}^2$
Step 3: Compute the area of triangle $AED$.
$\text{Area of triangle} = \frac{1}{2} \times \text{base} \times \text{height} = \frac{1}{2} \times 4 \times 4 = 8 \;\text{cm}^2$
Step 4: Sum the computed areas for the total area.
$\text{Total area} = 20 + 8 = 28 \;\text{cm}^2$
∴ Required Area = $28 \;\text{cm}^2$
In the figure O is the centre of the circle and A, B, C are points on the circle. AOB = 50^, BOC = 80^. 