Answer:
3x - 4 =9
Step-by-step explanation:
divide the entire equation by 3
9x/3 - 12/3 = 36/3
3x - 4 = 9
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:
X=8
Step-by-step explanation:
b is two fifths of c, so we make this a ratio with c = 1.
The ratio of b:c is 2/5 : 1
We also have 4a = 3c, rewrite this ratio so c is 1 by dividing both sides by 4,
so we get the ratio of a to c as 3/4 : 1
Now we get the a:b:c ratio of 3/4 : 2/5 : 1 now we can change the fractions to whole numbers, first by multiplying the 3 numbers by 4 to get get rid of the denominator of 4 in a:
3 : 8/5 : 4
Now multiply the 3 numbers by 5 to remove the denominator of 5 in b:
15 : 8 : 20
Now we can check using the equations:
b is 2/5 of c: 20 x 2/5 = 40/5 = 8 This is true.
4a = 3c: 4(15) = 3(20) = 60 = 60, this is also true.
The ratios is 15 : 8: 20
