CUET Preparation Today
CUET
General Test
Logical and Analytical Reasoning
Counting of Figures
How many triangles are there in the figure ?
11
12
13
14
Here
When n is odd:
No. of triangles = \(\frac{n\;(n\;+\;2)(2n\;+\;1)\;-\;1}{8}\)
= \(\frac{3\;(3\;+\;2)(6\;+\;1)\;-\;1}{8}\)
= \(\frac{105\;-\;1}{8}\) = 13
