Octagon, stop sign.
Eight isoscles triangles. It looks like we're told the side is 9.9 and the height to the side (also called the apothem) is 12.
So each isosceles triangle has area (1/2)(9.9)(12) and we have eight of them,
area = 8(1/2)(9.9)(12) = 475.2
Answer: 475.2
Usually we wouldn't be told 9.9 -- this is the baby version. We know each of those isoscles triangles has unique angle 360/8=45 degrees, so the apothem and half the side of the octagon are a right triangle with acute angle 22.5 degrees.
The area of the right triangle with long leg 12, short leg x,
tan 22.5 = x/12 or
x = 12 tan 22.5
Twice that is what we're told is 9.9; let's check:
2x = 24 tan 22.5 = 9.941125496954282
The area of the little right triangle is
(1/2) 12 × 12 tan 22.5
and there are 16 of these
16 (1/2) 12 × 12 tan 22.5 ≈ 477.174
A/2.8 • 2.8
Division and multiplication are opposite of each other, meaning they cancel out.
This means that a/2.8 • 2.8 is a.
No matter what a is equal to, the answer is a itself.
Once a is divided by 2.8, it is then multiplied by 2.8, bringing us back to the original value of a.
Answer:
a/2.8 • 2.8 = a
Hope this helps!
Answer is:
a) 32
b) 59
Both are arithmetic sequences
Area of sandbox = 169 square feet
Area of square with side 'x' is given by the formula = 
We have to determine the total length of wood Drew needs to make the sides of the sandbox.
Total length of wood required would be equal to perimeter of sandbox.
Let 'a' be the side of the square sandbox.
So, Area of sandbox = 169
a = 13 feet
Total length of wood required to make sides of the sandbox = Perimeter of the square sandbox = 
= 
= 52 feet.
Therefore, 52 feet of wood is required to make the sides of the square sandbox.
