Answer:
11.0
Step-by-step explanation:
Using Pythagoras' identity in the lower right triangle.
let the hypotenuse be x , then
x² = 4² + 9² = 16 + 81 = 97
Within the rectangle, use Pythagoras' identity in the lower right triangle.
let y be the dotted line , then
y² = x² + 5² = 97 + 25 = 122 ( take the square root of both sides )
y = ≈ 11.0 ( to the nearest tenth )
The dotted line is approximately 11.0 units