Welcome back — been a while! Let's pick up where you left off.
The question asks to find the area and perimeter of a sector of a circle with a radius of 21 cm and an angle of 120∘.
Given:
Radius, r=21 cm
Angle, θ=120∘
Step 1: Calculate the area of the sector.
The formula for the area of a sector is A=360∘θ×πr2.
A=360∘120∘×722×(21cm)2
A=31×722×441cm2
A=31×22×63cm2
A=22×21cm2
A=462cm2
The area of the sector is 462cm2.
Step 2: Calculate the perimeter of the sector.
The formula for the perimeter of a sector is P=360∘θ×2πr+2r.
P=360∘120∘×2×722×21cm+2×21 cm
P=31×2×22×3cm+42 cm
P=44cm+42 cm
P=86 cm
The perimeter of the sector is 86cm.
Send me the next one 📸