COMEDK · Maths · 4. Permutation Combination
A regular polygon of \(n\) sides has 170 diagonals, then \(n\) is equal to
- A -20
- B -17
- C 24
- D 20
Answer & Solution
Correct Answer
(D) 20
Step-by-step Solution
Detailed explanation
The number of diagonals in a polygon with \(n\) sides is given by the formula \(D = \dfrac{n(n-3)}{2}\). Given that the number of diagonals is 170, we set up the equation: \(\dfrac{n(n-3)}{2} = 170\) \(n(n-3) = 340\) \(n^2 - 3n - 340 = 0\) To solve this quadratic equation, we…
See the Complete Solution
Get step-by-step explanations for this and 2.5 Lakh+ more JEE, NEET & CET questions.
- Unlock all solutions
- Practice the full chapter
- Track accuracy across PYQs
4.8 rated on Google Play · 14,000+ reviews
More questions from Maths
- The probability that a randomly chosen number from one to twelve is a divisor of twelve isCOMEDK 2024 Easy
- The equation of an ellipse, whose focus is \((1,0)\), directrix is \(x=4\) and whose eccentricity is a root of the quadratic equation \(2 x^2-3 x+1=0\), isCOMEDK 2024 Medium
- If \(f(x)=\left\{\begin{array}{lc}x^2+1 & x \lt 0 \\ x^3-a & 0 \leq x \lt 1 \text { and it is continuous } \\ 2 b-x & x \geq 1\end{array}\right.\) \(\forall x \in R\), thenCOMEDK 2024 Easy
- The degree of the differential equation \(\left[1+\left(\dfrac{d y}{d x}\right)^2\right]^{\dfrac{3}{4}}=\left(\dfrac{d^2 y}{d x^2}\right)^{\dfrac{1}{3}}\)COMEDK 2025 Medium
- A student answers a multiple choice question with 5 alternatives, of which exactly one is correct. The probability that he knows the correct answer is \(p, 0 < p < 1\). If he does not know the correct answer, he randomly ticks one answer. Given that he has answered the question correctly, the probability that he did not tick the answer randomly, isCOMEDK 2021 Hard
- Simplified expression of \(1-\dfrac{\sin ^2 y}{1+\cos y}+\dfrac{1+\cos y}{\sin y}-\dfrac{\sin y}{1-\cos y}\) isCOMEDK 2025 Medium
More PYQs from COMEDK
- Find the general solution of \(\sin 2 x+\cos x=0\).COMEDK 2022 Medium
- The electric field versus distance graph is shown as given. Select the correct statement from the following.
E- electric field
R-radius
r - distance from the centre
COMEDK 2025 Medium - \(\int \sqrt{x^2-4 x+2} d x=\)COMEDK 2024 Medium
- Quality factor of a series \(L-C-R\) circuit decreases from 3 to 2 . Resonant frequency is \(600 \mathrm{~Hz}\). Change in bandwidth isCOMEDK 2016 Hard
- A particle on the trough of a wave at any instant will come to the mean position after a time \((T=\) time period \()\)COMEDK 2017 Easy
- Which of these represents the correct order of decreasing bond order?COMEDK 2023 Medium