Using Euler's formula,find the unknown:

Using Euler's formula,find the number of faces if the number of vertices is 6 and the number of edges is 12.

Verify Euler's formula for these solids.

Set up equation and solve to find the unknown numbers in the following case: Add 4 eight time a number, you get 60.

Set up equations and solve them to find the unknown numbers in the following cases: One-fifth of a number minus 4 gives 3.

Set up equations and solve them to find the unknown numbers in the following cases: If I take three-fourths of a number and add 3 to it. I get 21.

Set up equations and solve them to find the unknown numbers in the following cases: When I subtracted 11 from twice a number the result was 15.

Set up equations and solve them to find the unknown numbers in the following cases: Munna subtracts thrice the number of notebooks he has from 50, he finds the result to be 8.

In the adjoining figure, p||q. Find the unknown angles.

Consider the following parallelograms.Find the values of the unknown x,y,z.

Write the formula to find the volume of the sphere.