Answer:
z=10
Step-by-step explanation:
We know that the ratio 7:21 is equal to the ratio of 10:3z.
Let's model that in proportions:
7 10
- = -
21 3z
Now that the equation is in proportional form, we can cross-multiply to find the value of z.
7 * 3z = 21 * 10 - Multiply both sides
21z = 210 - Divide both sides by 21
z=10
The answer is z=10.
