Identify Congruent Triangles to a Given Isosceles Triangle (5th Grade Math)

Question

6. Circle all the triangles that are congruent to the first triangle. The first triangle is an isosceles triangle with a vertical line of symmetry (marked with a dashed line). The other triangles are: a scalene triangle, an isosceles triangle matching the first, a right triangle, an isosceles triangle with different angle, a triangle with a circle mark (congruent), a triangle with a slash mark (not congruent), a triangle with a circle and slash (congruent).

Accepted Answer

Circle the 3rd, 5th, and 7th triangles (the isosceles triangle matching the first, the triangle with the circle mark, and the triangle with the circle and slash mark).

Answer

Step 1: Recall that congruent triangles have exactly the same shape and size, meaning all corresponding sides and angles are equal. Step 2: Compare each triangle to the first (isosceles, symmetric with two equal sides and equal base angles). Step 3: Identify triangles with identical shape and size: the triangle that is a mirror image of the first, the triangle marked with a circle (same size and shape), and the triangle marked with a circle and slash (same size and shape).