Matching sides and angles of congruent figures
Grade 8 Math Worksheet
Circle the best answer, or write your answer on the line.
Ari turns triangle ABC 90° counterclockwise about the origin on the grid to make triangle A′B′C′. What is the perimeter of A′B′C′?
Bo flips triangle ABC over the y-axis on the grid to make triangle A′B′C′. What is the perimeter of A′B′C′?
Esme turns triangle ABC 180° about the origin on the grid to make triangle A′B′C′. What is the perimeter of A′B′C′?
Jun slides triangle ABC 9 units left and 2 units down on the grid to make triangle A′B′C′. What is the perimeter of A′B′C′?
Kira makes shape B from shape A with these moves: slide 6 units right, flip over a vertical line, then turn 90°. Is shape B congruent to shape A?
- No: every move changes the lengths a little.
- Yes: slides, flips and turns keep every length and angle.
- No: the flip turns B backward, so it no longer matches A.
- No: B sits in a different place, so it is a different shape.
Luz makes shape B from shape A with these moves: dilate by a scale factor of 2, then slide 4 units right. Is shape B congruent to shape A?
- Yes: the dilation keeps every angle, so B matches A.
- No: the dilation doubles every length, so B is twice as big as A.
- Yes: moves keep a shape's lengths the same.
- Yes: the last move was a slide, which keeps the size.
Milo makes shape B from shape A with these moves: turn 90°, dilate by a scale factor of 1/2, then flip over a horizontal line. Is shape B congruent to shape A?
- Yes: the last move was a flip, which keeps the size.
- Yes: the dilation keeps every angle, so B matches A.
- Yes: turns, dilations and flips all keep the lengths the same.
- No: the dilation halves every length, and nothing doubles them back.
Pia knows triangle DFG is congruent to triangle STU, with D↔U, F↔T and G↔S. How long is side DF?
Ren knows triangle KLM is congruent to triangle PQR, with K↔Q, L↔P and M↔R. How long is side KL?
Tala knows triangle WXY is congruent to triangle GHJ, with W↔H, X↔G and Y↔J. How long is side WX?
