In a right-angled triangle, one of the legs is 5 dm, and the second is 4 times larger. Find the area of this triangle.

In order to find the area of a right-angled triangle, we will apply the formula:

S = 1/2 * a * b.

The area of a right-angled triangle is half the product of the legs of this triangle.

Let’s start by analyzing the problem statement. The condition says that in a right-angled triangle one of the legs is 5 dm, and the second is 4 times larger.

That is, before finding the area, we must find the length of the second leg. It is known that the second leg is 4 times larger than the first:

5 * 4 = 20 dm.

S = 1/2 * 5 * 20 = 5 * 10 = 50 dm ^ 2.