The number of triangles in above figure is

The correct answer is Option (2) → 10

To count triangles without missing or repeating any, name every corner and crossing point and then count the triangles by size. The star is drawn with five straight lines (AC, AD, BD, BE, CE), which cross at P, Q, R, S and T.

Small triangles (the five points of the star):

• ATP, BPQ, CQR, DRS, EST

Large triangles (one whole line of the star as the base, with the two lines from its ends meeting at a crossing point):

• ACS, ADQ, BDT, BER, CEP

The inner pentagon PQRST is not a triangle, so the total is \(5+5=10\).