Question. Mark made a chalkboard that is 3 feet wide. It is 2 times as long as it is wide. What is the area of the chalkboard?
Answer. 18
What step-by-step reasoning justifies that answer?
Reasoning: The length of the chalkboard is 2 x the width of 3 feet = 6 feet. We can calculate area by multiplying the width and the length, so 3 feet x 6 feet = 18 feet.