BPSC – Combined Competitive Examination · প্রশ্ন 52
How many triangles are there in figure PQRS? (Figure: rectangle PQRS with both diagonals meeting at centre O, plus one horizontal segment from the left side to O and one vertical segment from O down to the bottom side.)
উত্তর দেখান ও ব্যাখ্যা
উত্তর: (D) 12
ব্যাখ্যা
Diagonals of a rectangle form 8 triangles; two centre-to-side segments each add 2 more, giving 12.
- (A) ভুল
Wrong: overcounts; the extra segments add only 4 triangles.
- (B) ভুল
Wrong: undercounts the triangles made by the extra segments.
- (C) ভুল
Wrong: overcounts.
- (D) সঠিক
Correct: diagonals give 8 triangles (4 small + 4 large); each extra segment splits one small triangle into 2, adding 4: total 12.