The ratios are equivalent because you multiplied 18:4 by 2&3. And also you divided it by 2. I had the same homework!
Answer
t3/b=x
Step by step explanation
t = bx/3
Take b/3 to the left hand side
= x = 3t/b
Hope it helped !!
Comment below

Step-by-step explanation:

Take
as common. Then,

S = 2 * (pi) * r * h.....for r
divide both sides by 2 * pi * h
s / (2(pi)h = r
Can write 3x or 3(x) or 3•x