36 ways... I believe... Do people ever answer questions on Brainly? Never had mine answered before.
First, recall that the equation of a line is
y = mx+b
where
m = slope
b = y-int
The key to this question is the details :
Horizontal line ---> This tells you that your slope is 0
y-int = 3.5 -----> In the equation above, b=3.5
Therefore,
y = 0x + 3.5
y = 0 + 3.5
y = 3.5
Let no red ribbons=x
no. Of blue ribbons=x+3
No. Of yellow ribb9ns=x+7
Totsl ribbons=28
28=x+x+3+x+7
28=3x+10
3x=28-10
3x=18
X=18/3
X=6
No .of red ribbons=6
No. Of blue ribbons=x+3=9
No. Of yellow ribbons=x+7=13
-3x+13=16
Move +13 to the other side. Sign changes from +13 to -13.
-3x+13-13=16-13
-3x=16-13
-3x=3
Divide by -3 for both sides.
-3/-3x=3/-3
Cross out -3 and -3, divide by -3, then becomes 1*1*x=x
x=-1
Answer: x=-1
A = 1/4 * (pi) * d^2
A = 1/4 * (pi) * 8^2
A = 1/4 * (pi) * 64
A = 1/4(64) * (pi)
A = 64/4 * (pi)
A = 16 (pi) in^2