# The angle of one triangle is 30 ° and the other is 60 ° Determine if these triangles are similar

A triangle is three points that do not lie on one straight line, connected by segments. In this case, the points are called the vertices of the triangle, and the segments are called its sides.

Similar triangles are triangles in which the angles are respectively equal, and the sides of one are respectively proportional to the sides of the other triangle.

In order to find out whether these triangles will be similar, you need to calculate the degree measures of all their angles.

Since we know the degree measures only for one angle for each triangle, we assume that these triangles are right-angled:

A rectangular triangle is a triangle in which one of the angles is 90º.

∠С = ∠С1 = 90º.

Since the sum of all the angles of the triangle is 180º, then

∠А = 180º – ∠В – ∠С;

∠А = 180º – 30º – 90º = 60º;

∠В1 = 180º – ∠А1 – ∠С1;

∠В1 = 180º – 60º – 90º = 30º.

∠А = ∠А1 = 60º;

∠В = ∠В1 = 30º.

Answer: if the given triangles are right-angled, then their corresponding angles are equal, and the triangles are similar.