4.37 $\mathrm{ft}$ ladder leans against a building so that the angle between the ground and the ladder is $81^{\circ}$. How high does the ladder reach on the building? Round answer to one decimal place. $\mathrm{ft}$

Step 1 ：The problem is asking for the height that the ladder reaches on the building. This is a right triangle problem where the ladder is the hypotenuse. We can use the sine of the angle to find the height. The sine of an angle in a right triangle is defined as the length of the opposite side (the height we are trying to find) divided by the length of the hypotenuse (the length of the ladder).

Step 2 ：So, we can set up the equation as follows: \(\sin(81) = \frac{height}{4.37}\).

Step 3 ：Solving for height gives us: \(height = \sin(81) * 4.37\).

Step 4 ：Final Answer: The ladder reaches a height of \(\boxed{4.3}\) ft on the building.