Question

What percent of the total area of the rectangle is colored?

Answer 1

Area of rectangle $=$ $L\times W$
The diagonal of the rectangle cuts the rectangle in two equal parts.
This can be proved as: The triangle formed is $45-45-90$.
Area of triangle $=$ $\frac{1}{2}\times L\times W$
Similarly the other diagonal cuts the area in two equal parts.
Hence, the total area of rectangle colored $=$ $\frac{1}{2}\times$ Area of triangle
$=$ $\frac{1}{4}$
$=$ $25$ $\%$