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:
area is 200 perimeter is 66
Step-by-step explanation:
Answer:
Step-by-step explanation:
805/38= 21 7/38
So that is 21 full payments of $38.00 and one of $7.00
Answer:
108,000 joules
Step-by-step explanation:
Kinetic energy, k = 1/2 mv^2
Where,
m = mass of the object in kilogram
v = velocity in meters per seconds
If
Velocity of an object = 20 meters per seconds
Kinetic energy = 48,000 joules
Solve for m
k = 1/2 mv^2
48,000 = 1/2 × m × 20^2
48,000 = 1/2 × m × 400
48,000 = 200m
m = 48,000 / 200
m = 240 kg
If it speeds up to 30 meters per second, then what is its new kinetic energy?
k = 1/2 mv^2
Using m = 240 kg
k = 1/2 mv^2
= 1/2 × 240 × 30^2
= 1/2 × 240 × 900
= 216,000 / 2
= 108,000 joules
The new kinetic energy = 108,000 joules
Answer:
8.3869278
Step-by-step explanation:
