Triangles MCQs

Q1. A carpenter nails together a triangular roof truss whose two lower joints open to 70 degrees and 55 degrees; what does the remaining joint measure?

• A.110 degrees
• B.235 degrees
• C.125 degrees
• D.55 degrees

Answer: D. 55 degrees

The interior angles of a triangle add to 180 degrees, so the third = 180 - (70 + 55) = 180 - 125 = 55 degrees.

Q2. A sailmaker stitches a triangular jib and finds its two lower corners come to 48 degrees and 67 degrees; how wide is the top corner of the sail?

• A.115 degrees
• B.132 degrees
• C.113 degrees
• D.65 degrees

Answer: D. 65 degrees

The interior angles of a triangle add to 180 degrees, so the third = 180 - (48 + 67) = 180 - 115 = 65 degrees.

Q3. A gardener pegs out a triangular herb bed and reads two of its corners as 34 degrees and 81 degrees on a protractor; what is the third corner?

• A.146 degrees
• B.65 degrees
• C.99 degrees
• D.115 degrees

Answer: B. 65 degrees

The interior angles of a triangle add to 180 degrees, so the third = 180 - (34 + 81) = 180 - 115 = 65 degrees.