Answer:
Length: 12 cm
Width: 8 cm
Height; 7 cm
Explanation:
We are told that the areas of 2 of the faces are 84cm² and 56cm².
Now, the side faces are 4 in total with 2 each having same areas.
Thus, it means they would have the same height.
Let's find the highest common factor between 84cm² and 56cm².
The highest number that can be divide each equally is 7.
Thus;
12 × 7 = 84 cm²
8 × 7 = 56 cm²
This means, the bottom part will measure 12 cm by 8 cm.
Thus, the complete measurement is;
Length: 12 cm
Width: 8 cm
Height; 7 cm
Let's check if it will give us a Volume equal to that given.
Thus;
Volume = 12 × 8 × 7 = 672 cm²
This is same as that given and so our dimensions are correct.