Vijayeemantra

I’m Up and Down, and Round and Round: CBSE Class 9 Mathematics practice questions

Practise 50 questions on I’m Up and Down, and Round and Round, free, with an explanation for each answer.

Start practising free

Sample questions

Ripples from a raindrop, the rings of a cut tree trunk, a sunflower head and the full moon all look like circles. Even early rock art shows circles. Which property does every circle have, and is used to define a circle?

Rock-art shapes, ripples on water, a tree-trunk slice, a sunflower and the moon
  1. It has no straight edges
  2. It has exactly one line of symmetry
  3. Every point on it is the same distance from one fixed point
  4. Its boundary is exactly twice as long as its width
Show the answer

C. Every point on it is the same distance from one fixed point

Every circle has a centre, and every point on the circle is at the same distance from it; this observation becomes the definition. An oval also has no straight edges, so that cannot define a circle. A circle has infinitely many lines of symmetry, and its boundary is about 3.14 times its width, not twice.

A and B are two points on a plane. How many different squares can be drawn with both A and B as corners (vertices)?

Two points A and B on squared paper, with one example square drawn faintly
  1. 1
  2. 2
  3. Infinitely many
  4. 3
Show the answer

D. 3

If AB is a side, the square can be built on either side of AB: 2 squares. If AB is a diagonal, the other two corners are fixed by the perpendicular bisector of AB: 1 square. Total 2+1=32 + 1 = 3. Infinitely many squares are possible only if A and B merely have to lie somewhere on the boundary.

Two parallel chords of 48 cm and 14 cm lie on the same side of the centre of a circle. The chords are 17 cm apart. Find the radius.

Two parallel chords of 48 cm and 14 cm on the same side of the centre, 17 cm apart
  1. 2424 cm
  2. 2525 cm
  3. 77 cm
  4. 3131 cm
Show the answer

B. 2525 cm

r2=242+x2=72+(x+17)2r^2 = 24^2 + x^2 = 7^2 + (x + 17)^2, so 576+x2=49+x2+34x+289576 + x^2 = 49 + x^2 + 34x + 289, giving 34x=23834x = 238 and x=7x = 7. Then r=242+72=625=25r = \sqrt{24^2 + 7^2} = \sqrt{625} = 25 cm (check with the shorter chord, 2424 cm from the centre: 72+242=25\sqrt{7^2 + 24^2} = 25 ✓). 77 cm stops at xx; 2424 cm is half the longer chord; 3131 cm adds 24+724 + 7 instead of using squares.

Topics covered

Start practising free

More CBSE Class 9 Mathematics chapters