1 Suppose that cand d vary inversely and that d = 2/9 (2 over 9) when c = 5.
Write a function that models the inverse variation and find d when c = 8.

d = 10/72

Step-by-step explanation:

c and d vary inversely

c = k/d

Where,

k = constant of proportionality

d = 2/9 when c = 5

c = k/d

5 = k ÷ 2/9

5 = k × 9/2

5 = 9k/2

Cross product

5*2 = 9k

10 = 9k

k = 10/9

c = k/d

c = 10/9 ÷ d

c = 10/9 × 1/d

c = 10/9d

find d when c = 8

c = 10/9d

8 = 10/9d

Cross product

8*9d = 10

72d = 10

d = 10/72