Are these triangles similar? (angle-angle)
Grade 8 Math Worksheet

Circle the best answer, or write your answer on the line.
Pia compares two kite panels, A and B. Are the two triangles similar?
- No: the first angles are 41° and 59°, so the two kite panels are not similar
- Yes: both have the angles 41°, 59° and 80°, so they are similar
- Not enough to tell: we need the side lengths first
Ren compares two gable ends, A and B. Are the two triangles similar?
Triangle A has angles 36° and 64°. Triangle B has angles 64° and 36° (sketch, not to scale). Triangle A has angles 36° and 64°. Triangle B has angles 64° and 36° (sketch, not to scale). 36° 64° Triangle A 64° 36° Triangle B Not to scale - No: the first angles are 36° and 64°, so they are not similar
- Yes: both have the angles 36°, 64° and 80°, so they are similar
- Not enough to tell: we need the side lengths first
Tala compares two mainsails, A and B. Are the two triangles similar?
Triangle A has angles 38° and 67°. Triangle B has angles 38° and 75° (sketch, not to scale). Triangle A has angles 38° and 67°. Triangle B has angles 38° and 75° (sketch, not to scale). 38° 67° Triangle A 38° 75° Triangle B Not to scale - Not enough to tell: we need the side lengths first
- No: A's angles are 38° and 67° but B's are 38° and 75°, so they are not similar
- Yes: both have the angles 38°, 67° and 75°, so they are similar
Zee compares two tent flaps, A and B. Are the two triangles similar?
Triangle A has angles 44° and 56°. Triangle B has angles 56° and 80° (sketch, not to scale). Triangle A has angles 44° and 56°. Triangle B has angles 56° and 80° (sketch, not to scale). 44° 56° Triangle A 56° 80° Triangle B Not to scale - No: A's angles are 44° and 56° but B's are 56° and 80°, so they are not similar
- Yes: both have the angles 44°, 56° and 80°, so they are similar
- Not enough to tell: we need the side lengths first
Bo checks two triangle warning signs, A and B. Are the two triangles similar?
Triangle A has angles 48° and 62°. Triangle B has angles 48° and 75° (sketch, not to scale). Triangle A has angles 48° and 62°. Triangle B has angles 48° and 75° (sketch, not to scale). 48° 62° Triangle A 48° 75° Triangle B Not to scale - Yes: both have a 48° angle, so they are similar
- No: A's angles are 48°, 62° and 70° but B's are 48°, 57° and 75°, so they are not similar
- Not enough to tell: we need the side lengths first
Kira compares two kite wings, A and B. We only know that each has a 50° angle. Are the triangles similar?
Triangle A and triangle B each have one angle marked 50°; their other angles are not known (sketch, not to scale). Triangle A and triangle B each have one angle marked 50°; their other angles are not known (sketch, not to scale). 50° Triangle A 50° Triangle B Not to scale - Not enough to tell yet: we need a second pair of equal angles
- Yes: they have an equal angle, so the two triangles are similar
- No: one equal angle means they are not similar
Luz compares two paper triangles, A and B. We only know that each has a 90° angle. Are the triangles similar?
Triangle A and triangle B each have one angle marked 90°; their other angles are not known (sketch, not to scale). Triangle A and triangle B each have one angle marked 90°; their other angles are not known (sketch, not to scale). 90° Triangle A 90° Triangle B Not to scale - Yes: they share an equal angle, so the two triangles are similar
- Not enough to tell yet: we need a second pair of equal angles
- No: one equal angle means they are not similar
Milo compares two tents, A and B. We only know that each has a 70° angle. Are the triangles similar?
Triangle A and triangle B each have one angle marked 70°; their other angles are not known (sketch, not to scale). Triangle A and triangle B each have one angle marked 70°; their other angles are not known (sketch, not to scale). 70° Triangle A 70° Triangle B Not to scale - Not enough to tell yet: we need a second pair of equal angles
- No: one equal angle means they are not similar
- Yes: they have one equal angle, so the two triangles are similar
Pia cuts two right-triangle sails, A and B. How many cm long is B's side across the 37° angle?
Triangle A: a right triangle with a 37° angle and a 53° angle; its side across 37° is 6 cm and its side across 53° is 8 cm. Triangle B: a right triangle with a 53° angle; its side across 53° is 24 cm. Angles are rounded to the nearest degree; the picture is not printed to size. Triangle A: a right triangle with a 37° angle and a 53° angle; its side across 37° is 6 cm and its side across 53° is 8 cm. Triangle B: a right triangle with a 53° angle; its side across 53° is 24 cm. Angles are rounded to the nearest degree; the picture is not printed to size. Triangle A 8 cm 6 cm 37° 53° Angles are rounded to the nearest degree; the picture is not printed to size. Not to scale. Triangle B 24 cm 53° Angles are rounded to the nearest degree; the picture is not printed to size. Not to scale. Zee cuts two right-triangle tents, A and B. How many cm long is B's side across the 53° angle?
Triangle A: a right triangle with a 53° angle and a 37° angle; its side across 53° is 12 cm and its side across 37° is 9 cm. Triangle B: a right triangle with a 37° angle; its side across 37° is 27 cm. Angles are rounded to the nearest degree; the picture is not printed to size. Triangle A: a right triangle with a 53° angle and a 37° angle; its side across 53° is 12 cm and its side across 37° is 9 cm. Triangle B: a right triangle with a 37° angle; its side across 37° is 27 cm. Angles are rounded to the nearest degree; the picture is not printed to size. Triangle A 9 cm 12 cm 53° 37° Not to scale. Triangle B 27 cm 37° Not to scale.

