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
-5(3+8x+3x^2) this was my answer I’m sorry if I’d gotten it wrong
9514 1404 393
Answer:
15 squre units
Step-by-step explanation:
The area of the rectangle is the product of its length and width. The length is AB = 5 units; the width is BC = 3 units. Then the area is ...
A = LW
A = (5 units)(3 units) = 15 units²
The area of rectangle ABCD is 15 square units.
Lets factor this quadratic function
the factors are (tan x + cos x)(tan x + cos x)
So the answer is choice A.
