Answer:
40 and 10
Explanation:
1. if the length is 'l' and height is 'h', then according to the condition 1/4*l=h.
2. if the given area is 400, it means, h*l=400;
3. if to substitute h=1/4*l into the formula of the area, then
l*l*1/4=400; ⇔ 1/4*l²=400;
4. if to calculate the value of the 'l', then l=40 (the required length).
5. if to substitute l=40 into 1/4*l=h, then h=10 (the required height).