A 25-ft lađider leans against a building so that the angle between the ground and the ladder is $83^{\circ}$. How high does the ladder reach on the building?

Step 1 ：This problem involves a 25-ft ladder leaning against a building, forming an angle of $83^{\circ}$ with the ground. We are asked to find how high the ladder reaches on the building.

Step 2 ：This is a trigonometry problem. We can use the sine function to solve it. The sine of an angle in a right triangle is defined as the length of the opposite side divided by the length of the hypotenuse. In this case, the ladder is the hypotenuse, the height the ladder reaches on the building is the opposite side, and the angle is $83^{\circ}$. We can set up the equation as follows: \(\sin(83^{\circ}) = \frac{height}{25ft}\).

Step 3 ：To solve for the height, we can rearrange the equation to get: \(height = 25ft * \sin(83^{\circ})\).

Step 4 ：Calculating the sine of $83^{\circ}$, we get approximately 0.992546151641322.

Step 5 ：Multiplying this by the length of the ladder (25 ft), we get approximately 24.81365379103305 feet.

Step 6 ：Final Answer: The ladder reaches approximately \(\boxed{24.81}\) feet high on the building.