The answer I believe is -36
Answer:
a = 14
Step-by-step explanation:
The mean is the sum of the values divided by the number of values.

Here, I think I can help you out:
1. 21 ÷ 3
= 7
Therefore, the length is 7cm².
2. 35 ÷ 7
= 5cm²
- And so on. Simply divide the area by the length of the side given; you can answer up to question six using this strategy.
7. All sides of a square are the same length.
7 x 7
= 49cm²
9. 2 x 3.5
= 7m²
- The formula to find the area of a square/rectangle is length x width. Just multiply the given lengths for the answers :)