Answer:
<h2>54m²</h2>
Step-by-step explanation:
<h3>METHOD 1:</h3>
You can use the Heron's formula:

where
<em>p</em><em> - half of perimeter</em>
<em>a, b, c</em><em> - lengths of sides</em>
We have

Calculate:

<h3>METHOD 2:</h3>
Let's check that it is not a right triangle.
If the sum of the squares of the two shorter sides is equal to the square of the longest side, then this triangle is rectangular.
We have

Check:

This is a right trianglr wherew 9m and 12m are legs and 15m is a hypotenuse.
The formula of an area of a right triangle is:

<em>a, b</em><em> - legs</em>
Substitute:

Answer:
65*h=c
Because if it's per hour c is dependent on the amount of hours.
I bet you're doing the Law of Sines right now. If you use the law of sines you find out that angle A is a 90 degree angle. There is only one triangle you can make with these measurements because if you have one angle of 30 and another of 90, the 3rd angle has to be a 60 degree angle. So it is a special right triangle, 30-60-90