On decreasing the radius of a sphere by 20%, by what per cent its volume will be decreased?

• 20

• 28.8

• 57.6

• 48.8

If the area of a circle is A, radius of circle is r and circumference ofit is C, the

• $\mathrm{rC} = 2\mathrm{A}$

• $\frac{\mathrm{C}}{\mathrm{A}} = \frac{{\displaystyle \mathrm{r}}}{2}$

• $\mathrm{AC} = \frac{{\mathrm{r}}^2}{4}$

• $\frac{\mathrm{A}}{\mathrm{r}} = \mathrm{C}$

Three solid spheres of radii 3 cm, 4 cm and 5 cm respectively are melted and made a large solid sphere. Radius of this sphere

• 12

• 10

• 6

• 4

What is the area of an equilateral triangle of side 16 cm?

• $48\sqrt{3} \mathrm{sq}.\mathrm{cm}$

• $128\sqrt{3} \mathrm{sq} \mathrm{cm}$

• $96\sqrt{3} sq cm$

• $64\sqrt{3} \mathrm{sq} \mathrm{cm}$

Class VI students were given the following layout of a house

The students were asked to find out the

A. perimeter and area of each room

B. total perimeter and total area of the
house.

The above activity can be used by teacher as
formative assessment task because

• the students will find the task interesting and
  will not disturb each other

• it will remove the phobia of Maths examination

• it will be easy for teacher to engage all the students for 40 min period

• the students' responses will help teacher to diagnose their understanding regarding finding dimensions, calculations, knowledge of formulae for perimeter and area etc.

Student's ability to apply the concept of square roots in real life situation can be assessed through the following problem.

• Find the smallest number that may be subtracted from 5607 to get a perfect square

• 2025 plants are to be planted in a garden in such a way that each row contains as many plants as the number of rows. Find the number of rows and number of plants in each row

• Find the smallest square number that is divisible by each of the numbers 4, 9 and 10

• Calculate the square root of 25600

42 cubes each of side 1 cm are glued together to form a solid cuboid. If the perimeter of the base of the cuboid is 18 cm, then its height (in cm)

• 3

• 4

• 1

• 2

In $∆$PQR, PQ = 4 cm, PR = 6 cm and QR = 3 cm. Which of the following is correct

• $\angle \mathrm{Q} = \angle \mathrm{R}$

• $\angle R < \angle P$

• $\angle \mathrm{R} > \angle \mathrm{Q}$

• $\angle \mathrm{Q} > \angle \mathrm{R}$

$\mathrm{In} ∆\mathrm{ABC} \mathrm{and} ∆\mathrm{LMN}, \mathrm{AB} = \mathrm{LM}, \mathrm{AC} = \mathrm{LN} \mathrm{and} \mathrm{LB} = \mathrm{ZM}.\mathrm{Then}, \mathrm{the}$

• triangles will be congruent if $\angle$B is a right anglE

• triangles are congruent only if AB= AC

• triangles cannot be congruent

• triangles must be congruent

The area of a trapezium-shaped field is 720 m, the distance between the two parallel sides is 20 m and the length of one of the parallel sides is 35 m. The length of the other parallel side is

• 37m

• 40m

• 35m

• 36m