Re: In the above figure, what is the ratio of area
[#permalink]
20 Aug 2025, 10:48
In the square ABCD above, $\(\mathrm{DE}=\mathrm{DC}-\mathrm{EC}=5-\mathrm{x}\)$, so the area of right triangle ADE is $\(\frac{1}{2} \times\)$ Base $\(\times\)$ Height $\(=\frac{1}{2} \times \mathrm{AD} \times \mathrm{DE}=\frac{1}{2} \times(5-\mathrm{x}) \times 5=\frac{5(5-\mathrm{x})}{2}\)$
Next the area of square $\(\mathrm{ABCD}=(\text { Side })^2=5^2=25\)$
So, the ratio of the area of triangle ADE and square ABCD is $\(\frac{5(5-\mathrm{x}) / 2}{25}=\frac{5(5-\mathrm{x})}{50}=\frac{(5-\mathrm{x})}{10}\)$ Hence the answer is (A).