Direct Proportion: 𝑦 ∝ 𝑥
1. For each table of values, state whether or not 𝑦 ∝ 𝑥.
(a)
(c)
(e)
𝒙
0
1
2
3
𝒚
0
4
8
12
𝒙
0
1
2
3
𝒚
2
5
8
11
𝒙
1
2
3
4
𝒚
2.5
5
7.5
10
(b)
(d)
(f)
𝒙
2
4
6
10
𝒚
10
20
36
50
𝒙
2
4
8
16
𝒚
16
8
4
2
𝒙
0
2
4
10
𝒚
0
𝑛
2
𝑛
5𝑛
2
2. 𝑥 and 𝑦 are variables such that 𝑥 ∝ 𝑦 and 𝑦 = 5 when 𝑥 = 2.
Which is the correct graph for these variables?
A 𝑦
B 𝑦
C 𝑦
D 𝑦
2
5
5
5
0
0
0
𝑥
2
0
0
𝑥
2
5
0
0
𝑥
2
𝑥
0
5
𝑥
6
8
16
32
0
3. 𝑥 and 𝑦 are variables such that 𝑥 ∝ 𝑦 and 𝑦 = 6 when 𝑥 = 5.
Which is the correct graph for these variables?
A 𝑦
B 𝑦
C 𝑦
D 𝑦
18
15
8
6
0
12
0
0
𝑥
5
0
0
𝑥
15
0
0
𝑥
4. In each table, 𝑥 ∝ 𝑦. Work out the missing values.
(a)
𝒙
𝒚
(c)
0
0
1
6
𝒙
𝒚
30
4
0
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0.6
𝒙
2.5
5
1.5
(b)
2
𝒚
𝒙
(d)
𝒚
4
6
4
1
6
1
3