Triangle Transformations and Congruence

Mr. Dell explains a problem involving rigid transformations from CPM's course. The video covers setting up a graph, drawing triangle T, translating it to form triangle A, and reflecting it to form triangle B. The congruency of triangles T, A, and B is discussed, emphasizing that rigid transformations do not alter angles or side lengths.

What is the first step in solving the problem involving rigid transformations?

• Drawing a circle

• Setting up a graph with x and y axes

• Calculating angles

• Measuring side lengths

Where should the vertices of triangle T be placed on the graph?

• (1, 2), (3, 2), (4, 4)

• (0, 0), (2, 2), (3, 3)

• (1, 1), (5, 1), (6, 3)

• (2, 1), (4, 1), (5, 2)

What is the result of translating triangle T left by 3 units and down by 4 units?

• Triangle A with vertices at (1, 1), (5, 1), (6, 3)

• Triangle A with vertices at (-1, -1), (1, -1), (2, 0)

• Triangle A with vertices at (0, 0), (3, 0), (4, 2)

• Triangle A with vertices at (-2, -3), (2, -3), (3, -1)

How do the coordinates change when reflecting triangle T across the y-axis?

• The x-coordinates change sign, y-coordinates remain the same

• Neither x nor y-coordinates change

• The x-coordinates remain the same, y-coordinates change sign

• Both x and y-coordinates change sign

Why are triangles T, A, and B considered congruent?

• They are all translated in the same direction

• They have different shapes but the same size

• Rigid transformations do not alter angles or side lengths

• They are all reflected across the same axis