Add 3 and 7. then multiply by 3.

30

Step-by-step explanation:

First, add 3 and 7

3 + 7 =10

The multiply by 3

10*3= 30

Hope this helps!

for ex: the reciprocal of 3/4 is 4/3. it is the opposite.

reciprocal definition:

a mathematical expression or function so related to another that their product is one; the quantity obtained by dividing the number one by a given quantity.

it would be:

c.parallelogram.