What is the number of diagonals of an octagon ? from Mathematics

Previous Year Papers

Download Solved Question Papers Free for Offline Practice and view Solutions Online.

Test Series

Take Zigya Full and Sectional Test Series. Time it out for real assessment and get your results instantly.

Test Yourself

Practice and master your preparation for a specific topic or chapter. Check you scores at the end of the test.
Advertisement

 Multiple Choice QuestionsMultiple Choice Questions

81.

Let m and n (m < n) be the roots of the equation x2 – 16x + 39 = 0. If four terms p, q, r and s are inserted between m and n to form an AP, then what is the value of p + q + r + s ?

  • 29

  • 30

  • 32

  • 35


Advertisement

82.

What is the number of diagonals of an octagon ?

  • 48

  • 40

  • 28

  • 20


D.

20

Number of diagonal in any polygon = nn - 32 {here, n = number of sides}

Then, number of diagonal in an octagon = 88 - 32 = 8 × 52 = 20 {for octagon n = 8}

Hence, option D is correct.


Advertisement
83.

A geometric progression (GP) consists of 200 terms. If the sum of odd terms of the GP is m, and the sum of even terms of the GP is n, then what is its common ratio ?

  • m/n

  • n/m

  • m + (n/m)

  • n + (m/n)


84.

If x2 - 3x + 2 > x2 - 3x +2, then which one of the following is correct ?

  • x  1 or x  2

  • 1  x  2

  • 1 < x < 2

  • x is any real value except 3 and 4


Advertisement
85.

If the roots of the equation

a(b - c)x2 + b (c – a)x + c(a - b) = 0

are equal, then which one of the following is correct ?

  • a, b and c are in AP

  • a, b and c are in GP

  • a, b and c are in HP

  • a, b and c do not follow any regular pattern


86.

If the sum of first n terms of a series is (n + 12), then what is its third term ?

  • 1

  • 2

  • 3

  • 4


87.

What is the value of 1 – 2 + 3 – 4 + 5 ... + 101 ?

  • 51

  • 55

  • 110

  • 111


88.

If the angle of a triangle ABC are in AP and b : c = 3 :2, then what is the measure of angle A ?

  • 30°

  • 45°

  • 75°

  • 60°


Advertisement
89.

Arithmetic meanof 10 observation is 60 and sum of squares of deviations from 50 is 5000. What is the standard deviation of the observation ?

  • 20

  • 21

  • 22, 36

  • 24, 70


90.

If (1 + 2x – x2)= a0 + a1x + a2x+ ... + a12x12, then what is a0 – a1 + a2 – a3 + a4 ... + a12 equal to ?

  • 32

  • 64

  • 2048

  • 4096


Advertisement