Answer:
a. i. 3000 cm² ii. 220 cm b. 6 feet
Step-by-step explanation:
A. i. The area of the sector AOB is A = ¹/₂r²θ where r = radius of circle = 50 cm and θ = angle subtended at the center of the circle by the sector in radians = 2.4 radians.
So, A = ¹/₂r²θ
= ¹/₂(50 cm)² × 2.4 rad
= ¹/₂ × 2500 cm² × 2.4 rad
= 1250 cm² × 2.4 rad
= 3000 cm²
ii. The perimeter of the sector is P = 2r + rθ = (2 + θ)r
substituting r and θ, we have
P = (2 + θ)r
= (2 + 2.4) × 50 cm
= 4.4 × 50 cm
= 220 cm
B. Since length of an arc L = rθ where r = radius = length of pendulum and θ = angle swept by pendulum = ½ radian and length of the arc swept = 3 feet, the radius is
r = L/θ
= 3 feet ÷ ½ rad
= 3 × 2
= 6 feet
