Answer:
60ft
Step-by-step explanation:
Let's x, y be the width and length of the surrounding rectangle. Since the area is 450 sq feet, this means xy = 450 or y = 450/x
The perimeter of this rectangle is (since there are 3 sides only)
f(x,y) = 2x + y
This is something we need to minimize. We can start by substituting y = 450/x
f(x) = 2x + 450/x
Let's take the first derivative of this function and set it to 0
y = 450 / 15 = 30ft
so the minimum perimeter that needs taping over is
f(x,y) = 2x + y = 2*15 + 30 = 60ft
%change=100*(final-initial)/initial
%change=100(42.95-15.99)/15.99=168.61% (to nearest hundredth of a percent)
Answer:
Area of sector = 144.4π cm²
Step-by-step explanation:
Given:
Perimeter of circle = 40π cm
Given angle = 130°
Find:
Area of sector
Computation:
Perimeter of circle = 2πr
⇒ 40π = 2πr
⇒ 40 = 2r
⇒ Radius r = 40 / 2
Radius r = 20 cm
Area of sector = [θ/360][π][r]²
⇒ Area of sector = [130/360][π][20]²
⇒ Area of sector = [0.361][π][400]
Area of sector = 144.4π cm²