Question

please answer this 2 questions,, it's toooooooooooooo urgent

Answer 1

39. Given the Diameter of the Broach as 21 cm ⇒ Radius = 21/2

Let us find the Area of the Circle = πr²

⇒ Area of the Circle = 22/7 × 21/2 × 21/2 = 11 × 3 × 10.5 = 346.5 cm²

As the wire divides the Circle into 10 Equal sectors

Area of each sector of the broach = 1/10 × Area of all sectors

we know that Area of all sectors = Area of Circle

Area of each sector of the broach = 1/10 × Area of Circle

but we got Area of Circle as 346.5 cm²

Area of each sector of the broach = 1/10 × 346.5 = 34.65 cm²

40. We know that Perimeter of the Circle = 2πr

     We know that Area of Circle = πr²

     Given that Perimeter of the circle and the Area of the circle are Equal

⇒  πr² = 2πr

⇒ r = 2

⇒ The radius of Circle whose perimeter and area are numerically equal is 2

41. Given that the side of the square as 7 cm

we know that Area of the square is given by side ×  side

⇒ Area of the Given square = 7 × 7 = 49 cm²

we can notice that the Area of the non-shaded portion is one quarter of the circle of radius 7cm

⇒ Area of the shaded portion = Area of the square - Area of the non-shaded portion

⇒ Area of the shaded portion = Area of the square - Area of the one quarter of the circle

⇒ Area of the shaded portion = 49 - 1/4(π × 7 ×7)

⇒ Area of the shaded portion = 49 - 1/4(22/7 × 7 × 7)

⇒ Area of the shaded portion = 49 - 1/4(22 ×7)

⇒ Area of the shaded portion = 49 - 38.5

⇒ Area of the shaded portion = 10.5 cm²