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
Answer:
1:4
Step-by-step explanation:
there are 60 minutes in an hour
60/15=4
15:60=1:4
The probability of a red marble is 25/250 or 1/10. The probability of a green marble is 50/250 or 1/5. The probability of a blue or orange marble is 175/250 or 7/10. Multiply the numerators and the denominators to get 7/500 probability (B)
Answer:
4
Step-by-step explanation:
Answer:
A. 13.31' to the nearest hundredth.
B. 86.52' to the nearest hundredth.
Step-by-step explanation:
Part A>
The apotherm of a regular polygon is the distance of the line segment from the centre of the polygon to the midpoint of a side.
2 radii of this decagon joined to the endpoints of a side form an isosceles triangle with equal sides = 14 cm.
The apotherm is the altitude of this triangle. The vertex of the triangle has an angle of 360 / 10 = 36 degrees and the apotherm bisects this angle.
So using trigonometry on the right triangle formed:
cos 18 = x / 14 where x is the apotherm.
x = 14 cos 18
= 13.31' (answer).
Part B.
Using trigonometry on the right triangle again:
sin 18 = x/2 / 14 (where x is the length of a side of the hexagon)
x/2 = 14 sin 18
x = 2 * 14 sin 18
= 8.652'.
As a decagon has 10 sides the perimeter = 8.652 * 10
= 86.52' to the nearest hundredth.
