What is the width w of the
entire garage?

Answer:
30 ft
Step-by-step explanation:
The large triangle above is divided into two right triangles by the dashed line.
Since we are dealing with right triangles, we can use the Pythagorean theorem.
For each right triangle:
a² + b² = c²
Let a = half of w (the horizontal leg).
Let b = 8 ft (the vertical leg).
Let c = 17 ft (the hypotenuse).
a² + 8² = 17²
a² + 64 = 289
a² = 225
a = 15
a is half of w.
w = 2a = 2 × 15 ft = 30 ft