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
Step-by-step explanation:
For quadratic equation ax^2 + bx + c = 0 to have two distinct real roots,
b^2 - 4ac must be positive.
b^2 - 4ac > 0
(k - 3)^2 - 4(3 - 2k) > 0
k^2 - 6k + 9 - 12 + 8k > 0
k^2 + 2k - 3 > 0
Answer:
Height of flagpole before it fell = 5.15 m
Step-by-step explanation:
Given:
Height of remain pole (p) = 1.7 m
Distance from base (b) = 3 m
Find:
Height of flagpole before it fell
Computation:
Using Pythagorean theorem
H = √ p² + b
Length of broken part = √ 1.7² + 3²
Length of broken part = √ 2.89 + 9
Length of broken part = √ 11.89
Length of broken part = 3.45 (Approx)
Height of flagpole before it fell = Length of broken part + Height of remain pole
Height of flagpole before it fell = 3.45 + 1.7
Height of flagpole before it fell = 5.15 m
25g = r , i think.
I would give an explanation but you seem in a hurry! Have a good day and good luck!
