Are these triangles similar? (angle-angle)

Answer Key - Grade 8 Math Worksheet - Building Confidence

Circle the best answer, or write your answer on the line.

1. 1.

   Bo sees triangle A on a sail. A has a 31° angle and a 54° angle. The sketch writes 180° beside the triangle. What is A's third angle?

   95
2. 2.

   Jun sees triangle A on a kite wing. A has a 77° angle and a 48° angle. The sketch writes 180° beside the triangle. What is A's third angle?

   55
3. 3.

   Kira enlarges a small sail A into a big sail B. The scale factor from A to B is 3. How many cm long is B's side across the 40° angle?

   54
4. 4.

   Zee compares two kite wings, A and B. Are the two triangles similar?

   • No: the angles do not all match, so they are not similar
   • Yes: both have a 40° angle, so they are similar
   • Not enough to tell: we need the side lengths first
5. 5.

   Bo compares two triangle warning signs, A and B. Are the two triangles similar?

   • Not enough to tell: we need the side lengths first
   • Yes: both have a 25° angle, so they are similar
   • No: the angles do not all match, so they are not similar
6. 6.

   Esme compares a small paper pennant A and a big paper pennant B. Are the two triangles similar?

   • Not enough to tell: we need the side lengths first
   • No: B is much bigger than A, so they are not similar
   • No: the lists start with 35° and 50°, so they are not similar
   • Yes: all three angles match, so they are similar
7. 7.

   Kira labels the corners of two similar tents. Triangle GHQ is the small one and triangle SUY is the big one. Which corner of SUY matches corner H?

   • corner Y
   • corner U
   • corner S
8. 8.

   Luz labels the corners of two similar sails. Triangle SUV is the small one and triangle WYC is the big one. Which corner of WYC matches corner V?

   • corner C
   • corner Y
   • corner W
9. 9.

   Milo labels the corners of two similar roofs. Triangle DFG is the small one and triangle HQS is the big one. Which corner of HQS matches corner G?

   • corner Q
   • corner H
   • corner S
10. 10.

    Noah labels the corners of two similar kites. Triangle WYC is the small one and triangle DFG is the big one. Which corner of DFG matches corner Y?

    • corner F
    • corner D
    • corner G