Answer:
72
Step-by-step explanation:
The perimeter of the pentagon with apothem of 5cm is 28.87cm
<h3>How to calculate the perimeter of a pentagon</h3>
The sum of all the external sides of the pentagon is its perimeter.
First we need to calculate the half of one of its sides using the SOH CAH TOA
tan 30 = x/5
x = 5 tan 30
x = 2.89
One of the sides = 2(2.89) = 5.77 cm
Perimeter of th pentagon = 5(5.77) = 28.87
Hence the perimeter of the pentagon with apothem of 5cm is 28.87cm
Learn more on perimeter of pentagon here: brainly.com/question/11484726
The double of 50 is 100 which means you would do 28*100=2800 now half of the answer is 2800/2=1400 which makes 1,400 your answer
Answer:
See below in bold.
Step-by-step explanation:
cos 4x = 2cos^2 2x - 1 = 2 (2 cos^2 x - 1)^2 - 1
and cos 2x = 2 cos^2 x - 1 so we have:
2 ( 2 cos^2 x - 1)^2 - 1 - (2cos^2 x - 1) = 0
2 ( 2 cos^2 x - 1)^2 - 2 cos^2 x = 0
(2 cos^2 x - 1)^2 - cos^2 x = 0
Let c = cos^2 x, then:
(2c - 1)^2 - c = 0
4c^2 - 4c + 1 - c = 0
4c^2 - 5c + 1 = 0
c = 0.25, 1
cos^2 x = 0.25 gives cos x = +/- 0.5
and cos^2 x = 1 gives cos x = +/- 1.
So for x = +/- 1 , x = 0, π.
For cos x = +/- 0.5, x = π/3, 2π/3, 4π3,5π/3.