3/9=21/k what is the strategy for solving it

Answer: k = 63

Step-by-step explanation: You need to multiply the left side by its reciprocal to move the numbers to the right. You also need to multiply by k on the right side to get it alone on the left. This will result in

(9/3) (3/9) = (21/k) (9/3) simplified

1 = 189/3k • k then multiply by k

k = 189/3 simplify

k = 63