All Exams Test series for 1 year @ ₹349 only
Question

The number of sides of a regular polygon whose exterior angles are each $40^\circ$ is:

This question was previously asked in
RRB NTPC 2015 CBT 1 Question Paper (29-Mar-2016) (Shift 1)
The correct answer is
9

Calculating Regular Polygon Sides

The problem asks for the number of sides of a regular polygon given that each exterior angle measures $40^\circ$.

Exterior Angle Formula

For any convex polygon, the sum of the exterior angles is $360^\circ$. In a regular polygon with 'n' sides, all exterior angles are equal. The formula relating the number of sides (n) and the measure of each exterior angle is:

$ \text{Exterior Angle} = \frac{360^\circ}{n} $

Solving for Number of Sides (n)

We are given that the exterior angle is $40^\circ$. We can substitute this value into the formula and solve for 'n':

  1. Set up the equation: $ 40^\circ = \frac{360^\circ}{n} $
  2. Rearrange the equation to solve for 'n': $ n = \frac{360^\circ}{40^\circ} $
  3. Calculate the value of 'n': $ n = 9 $

Therefore, the regular polygon has 9 sides.

Was this answer helpful?

Similar Questions

  1. The adjacent sides of a parallelogram are $4a$ and $3a$. If the angle between them is $60^{\circ}$, then one of the diagonals of the parallelogram will be:
  2. Every interior angle of a regular octagon is $135^\circ$. Find the exterior angle of the octagon.
  3. PQ is a diameter of circle whose centre is O. If a point R lies on a circle and $\angle RPO$ is $42^\circ$, then find $\angle RQP$.
  4. ABC is an equilateral triangle and O is its circumcentre. If the side of triangle is 6 cm, then the $\angle BOC$ is:
  5. If every interior angle of a regular polygon is $144^\circ$, then the polygon has ______ sides.
  6. The ratio of the numbers of sides of two regular polygons is $1 : 2$. If each interior angle of the first polygon is $140^\circ$, then the measure of each interior angle of the second polygon is:
  7. If the sum of the interior angles of a regular polygon is equal to four times the sum of its exterior angles, then what is the number of diagonals in the polygon?
  8. Find the ratio of the measure of an angle of a regular pentagon to that of a regular octagon.
  9. What is the measure of each exterior angle of a regular octagon?
  10. The difference between the interior and exterior angles at a vertex of a regular polygon is $140^\circ$. The number of sides of the polygon is:

Important Questions from Geometry

  1. The sides of a triangle are in the ratio 6 : 4 : 3 and its perimeter is 104 cm. The length of the longest side (in cm) is:

  2. An isosceles right-angled triangle has hypotenuse length as 10 units. What is the area of the triangle (in square units)?

  3. Two circles of radii 16 cm and 4 cm, respectively, touch each other externally at Point A. PQ is the direct common tangent of these circles with centres C1 and C2, respectively. What is the length of PQ?

  4. Let C be a circle with center O and AB be a chord of C such that the length of AB is equal to the radius of C. Let D be any point on the major arc of AB. Find ∠AOB and ∠ADB, respectively.

  5. The centres of two circles are 84 cm apart. If the radii of these two circles are 38 cm and 26 cm, respectively, then which of the following options gives the length (in cm) of a direct common tangent of these two circles?

Need Expert Advice?
Upcoming Exams
RRB NTPC
September 27, 2026
Test Series
RRB NTPC img
Railways
RRB NTPC Under Graduate 2026 New Mock Test Series
1580 Tests 2 Tests Free
386 Attempts
4.3(493)
English, Hindi, Telugu +7 More

Start Your Preparation with Prepp Mobile App

Download the app from Google Play & App Store
Download the app from Google Play & App Store
Prepp Mobile App