## What are the 3 ways to prove triangles are similar?

These three theorems, known as Angle – Angle (AA), Side – Angle – Side (SAS), and Side – Side – Side (SSS), are foolproof methods for determining similarity in triangles.

## Can ASA prove triangles similar?

3. ASA (angle, side, angle) If two angles and the included side of one triangle are equal to the corresponding angles and side of another triangle, the triangles are congruent.

Is SSA a similarity theorem?

Explain. While two pairs of sides are proportional and one pair of angles are congruent, the angles are not the included angles. This is SSA, which is not a similarity criterion. Therefore, you cannot say for sure that the triangles are similar.

How do you prove triangles?

The simplest way to prove that triangles are congruent is to prove that all three sides of the triangle are congruent. When all the sides of two triangles are congruent, the angles of those triangles must also be congruent. This method is called side-side-side, or SSS for short.

### How can you illustrate similar triangles?

If the two sides of a triangle are in the same proportion of the two sides of another triangle, and the angle inscribed by the two sides in both the triangle are equal, then two triangles are said to be similar. Thus, if ∠A = ∠X and AB/XY = AC/XZ then ΔABC ~ΔXYZ.

### What are two criteria for triangles to be similar?

By definition, two triangles are similar if all their corresponding angles are congruent and their corresponding sides are proportional. It is not necessary to check all angles and sides in order to tell if two triangles are similar.

Why does SSA not like similarity?

Knowing only side-side-angle (SSA) does not work because the unknown side could be located in two different places. Knowing only angle-angle-angle (AAA) does not work because it can produce similar but not congruent triangles. The same is true for side angle side, angle side angle and angle angle side.

Why does SSA not prove similarity?

If two triangles have two congruent sides and a congruent non included angle, then triangles are NOT NECESSARILLY congruent. This is why there is no Side Side Angle (SSA) and there is no Angle Side Side (ASS) postulate.

#### What type of proof is used in proving congruent triangles?

Angle-side-angle is a rule used to prove whether a given set of triangles are congruent. The ASA rule states that: If two angles and the included side of one triangle are equal to two angles and included side of another triangle, then the triangles are congruent.

#### How can you tell if two triangles are similar?

Two triangles are said to be similar if their corresponding angles are congruent and the corresponding sides are in proportion . In other words, similar triangles are the same shape, but not necessarily the same size.

Which type of triangles are always similar?

Isosceles triangles are not always similar, but equilateral triangles are always similar.