Question of Solved Question

Surface Area and Volume of Class 9

If h, c and v be the height, curved surface and volume of a cone, show that 3πvh3 – c2h2 + 9v2 = 0.

Frequently Asked Questions

Simplify the following expressions

(√(5) + √(2))2






Which of the following rational numbers lies between 0 and - 1

A: 0

B: - 1

C: -1/4

D: 1/4




0 and 1 cannot be found between 0 and 1.

In addition,0= o/4  and -1= -4/4

We can see that -1/4 is halfway between 0 and -1.

Final Answer:

Hence, the correct option is (c) -1/4


Prove that the diagonals of a parallelogram bisect each other



We must show that the diagonals of the parallelogram ABCD cross each other.

OA = OC & OB = OD, in other words.

Now AD = BC [opposite sides are equal] in ΔAOD and ΔBOC.

[alternative interior angle] ∠ADO = ∠CBO in ΔAOD and ΔBOC.

Similarly, ∠AOD = ∠BOC by ΔDAO = ΔBCO (ASA rule)

As a result, OA = OC and OB = OB [according to CPCT].

according to CPC

Final Answer:

Hence, it is prove that the diagonals of a parallelogram bisect each other.


What is total surface area of sphere



  • The radius of the sphere affects the formula for calculating the sphere's surface area. 
  • If the sphere's radius is r and the sphere's surface area is S.
  • The sphere's surface area is therefore stated as Surface Area of Sphere 4πr2, where ‘r’ is the sphere's radius.
  • The surface area of a sphere is expressed in terms of diameter as S=4π(d/2)2, where d is the sphere's diameter.

Final Answer:

Thus, total surface area of sphere is =4πr2.


Fill in the blanks If two adjacent angles are supplementary

 they form a __________.



  • If the non-common sides of two angles form a straight line, they are called linear pair angles. 
  • The sum of the angles of two linear pairs is  degrees.
  • If the total of two angles is  degrees, they are called supplementary angles.

Final Answer:

A linear pair is formed.


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