1. Proportions are relatively easy; we can reduce the fractions or check the cross product
4/20 = 1/5 not 1/6
28/36 = 7/9, CHECK
14/18=7/9, 21/27=7/9 CHECK
30/80=3/8, 6/18=1/3, nope
2. Let's check cross products on these
3(40)=120, 5(24)=120, no these are proportions
30(5)=150, 15(10)=150, no, proportions
9(4)=36, 3(14)=42, CHECK 9/14 is not 3/4
7(24)=14(12) true without multiplying it out; these are proportional
3.
4/16 = m/24
24(4) = 16 m
6(4)(4) = 16 m
Answer: m = 6
4.
t/16 = 40/50 = 4/5
5t = 16(4)=64
10t = 128
Answer: t = 12.8
