Step-by-step explanation:
Given:

Answer:
12
Step-by-step explanation:
Diagonals of a rhombus bisect each other at right angles, so in triangle JNK, we have JK=20 and JN=16.
Using the Pythagorean theorem, it follows that KN = 12.
He used 12 gallons of white paint.
Because 20 divided by 5 = 4. Meaning that 4 gallons is one part.
4 x 5 = 20
4 x 3 = 12