The area of a polygon is given by the formula Area = ap/2 where a is the length of the apothem and p is the perimeter. The apothem is a line from the center of the polygon perpendicular to a side.
Depending on the formula you know, you can find the length of a side in 1 of 2 ways.
The first way uses a triangle. Using the radius of the polygon you can create 8 congruent triangles. The center angle will be 360 / 8 = 45 and two side lengths of 20. You can find the length of the base using the law of cosines.
c^2 = 20^2 + 20^2 - 2(20)(20)(cos 45)
c^2 = 400 + 400 - 800(cos 45)
c^2 = 800 - 800(cos 45)
c = sqrt(800 - 800(cos 45)
c = 15.31
The second way is to use this formula:
r = s / (2 sin(180 / n))
20 = s / (2 sin(180/8)
(20)(2)sin(22.5) = s
(40)sin(22.5) = s
s = 15.31
We need to calculate the perimeter. As there are 8 sides (8)(15.31) = 122.48
Now we need to calculate the apothem using
a = S / (2 tan (180 / n)
a = 15.31 / (2 tan (180 / 8))
a = 18.48
Now solve for the area
Area = ap/2
Area = (18.48)(122.48)/2
Area = 1131.72
perimeter = 122.48
area = 1131.72
Answer:
cos(∅) = 3/5
Step-by-step explanation:
cos(∅) = adjacent/hypotenuse
We don't know what the hypotenuse is so we gotta use Pythagorean theorem to find it.
a² + b² = c²
4² + 3² = c²
√(4² + 3²) = c
c = 5 , this is our hypotenus
cos(∅) = adjacent/hypotenuse
cos(∅) = 3/5
Answer:$1304.89
Step-by-step explanation:
P(1 + r/n)^r*t
500 ( 1 + 0.08/52) ∧ 52*12
500 (1.00154)^624
500 ( 2.61)
1304.88523
