Answer:
The length of diagonal portion of the shower ledge is 1.44 ft .
Explanation:
By using the Pythagorean theorem in shower ledge portion .
Hypotenuse² = Perpendicular² + Base²
As shown in the diagram.
Take
Perpedicular = 1.2 ft
Base = 0.8 ft
Hypotenuse = Diagonal length
Put in the above
Diagonal length² = (1.2)² + (0.8)²
Diagonal length² = 1.44 + 0.64
Diagonal length² = 2.08

Diagonal length = 1.44 ft (Approx)
Therefore the length of diagonal portion of the shower ledge is 1.44 ft .