Triangular numbers: 1,3,6,10,15,21,28,36,45,55…. Hexagonal numbers:1,6,15,28,45…. Every hexagonal number is also a triangular number. The fifth hexagonal number (45) is the ______ triangular number.

Answer as guest — Start Free Practice Test to earn Practice PointsHow to earn pointsAsk a question+3Answer a question+1Someone answers yours+1Your Q gets upvoted+1Pioneer bonus (first 5)+5, ask questions & climb the leaderboard!

A 5th
B 8th
C 9th
D 10th

Show answer and explanation

Answer: C. 9th

The fifth hexagonal number 45 is written in 9th place in the triangular number in the question which is given above so the answer is 9th.

Answering after opening this box earns no Practice Points.

Rules for asking and answering

Triangular numbers: 1,3,6,10,15,21,28,36,45,55…. Hexagonal numbers:1,6,15,28,45…. Every hexagonal number is also a triangular number. The fifth hexagonal number (45) is the ______ triangular number.

More questions like this