To find area of full circle
A= pi*r^2
A=pi*20^2
A=1256 ft^2
Now figure only for the 3/4 of circle the building don’t cover
A=1256*.75
A=942 ft^2
So the area it can detect is 942 ft^2
Answer/Step-by-step explanation:
Recall: if two figures are similar, we know that the ratio of their areas = the square of the ratio of their corresponding sides
Apply this knowledge to solve the problems given.
✔️Problem 1 (4-sided polygon):
Let the missing area be x cm²
Therefore,



Multiply both sides by 9
x = 9*4
x = 36 cm²
✔️Problem 2 (3-sided polygon):
Let the missing area be y cm²
Therefore,



Multiply both sides by 240
y = ¹/16 × 240
y = 15 cm²
✔️Problem 3 (5-sided polygon):
Let the missing area be z cm²
Therefore,


Multiply both sides by 40


z = 90 cm²
If 80° ------> 88π cm
Then 360° ------> x cm
So:
x = (88π x 360) ÷ 80
x = 396 π (lenght of the circle)
The relationship of Lenght of circle and its diameter is:
L = d .π
replacing L:
396 π = d.π ----> d = 396 cm <---- here is your answer
This is assuming the sum of the two angles produces a straight line, or a 180° angle. Since the given angle is 121°, angle w must be 180-121, which is 59<span>°.</span>