In every 45-45-90 triangle, both legs have the same length and the hypotenuse has the length of a leg multiplied by √2.
The hypotenuse is the side opposite to the right angle (90º). The other two sides are the legs that have the same length.
In the question b., the hypotenuse has a length b and the missing leg has a length a.
Since the leg of the triangle has a measure of 2.5ft, then the leg a must have the same measure. Then:
The hypotenuse has the length of a leg multiplied by √2. Then:
Therefore, the lengths of a and b in the question b., are: