Question

A paper is in the form of a rectangle DARK in which DA=30 cm.and KD=21cm.A semicircular portion with AR as diameter is cut-off.Find the area of the remaining part.

Answer 1

We know that opposite sides in rectangle are equal, so DA = KR = 30 Cm and KD = AR = 21 CM, AR as diameter is cut-off, Now AKR is left, AKR becomes triangle.

Area triangle AKR = 1/2×Base×Height
                              = 1/2×  30  ×   21
                              = 15 ×  21
                              = 315 cm²

Answer 2

Question:-

★A paper is in the form of a rectangle DARK in which DA=30 cm.and KD=21cm.A semicircular portion with AR as diameter is cut-off.Find the area of the remaining part.

Solution:-

Area of DARK = (l×b)

= (30×20)

= 630 cm²

Area of semi-circle = $\frac{πr²}{2}$

= $\frac{22}{7}×{21}{2}\frac{2}$