Answer: H=12 and B=8
Looking at the problem, you are given the area, a , and told the h is 4 meters longer than b; in other words, h=b+4.
Since a=1/2bh, you can replace a with 48. Also, since h is b+4, you can replace that as well. You'd end up with this equation:
48=1/2b(b+4)
1. Seeing that 48 is 1/2 of b, you know that you have twice the value of 48, or 96. So, you can put that 96=b(b+4).
2. Now, thinking through factors of 96- 1 x 96, 2 x 48, 3 x 32, 4 x 24, 6 x 16, or 8 x 12, the only pair in which h is b+4 is 12 x 8.
Hope this helps,
Lacia :))