Question

1. classify the triangle by its sides. equilateral triangle scalene triangle isosceles triangle obtuse triangle

Explanation:

Step1: Recall triangle - side classification rules

A scalene triangle has no equal sides, an isosceles triangle has at least two equal sides, and an equilateral triangle has all three sides equal. An obtuse triangle is classified by angles (one angle > 90°).

Step2: Analyze the markings on the triangle

The triangle has tick - marks indicating that all three sides are equal.

Answer:

equilateral triangle