The acute angle of a right-angled triangle is 4 times larger than the other acute angle of this triangle.

The acute angle of a right-angled triangle is 4 times larger than the other acute angle of this triangle. Find the smaller angle of this triangle?

A right-angled triangle is a triangle, which has one angle of a straight line, that is, it is equal to 90 °. The sum of the interior angles of a triangle is 180 °.

1. One of the acute angles of the triangle is x degrees.

2. Another acute angle of the triangle is x * 4 = 4x degrees.

3. Let’s compose and solve the equation.

90 + x + 4x = 180;

5x = 180 – 90 = 90;

5x = 90;

x = 90/5 = 18;

x = 18;

Answer: The smallest acute angle of a right-angled triangle is x = 18 °.