<u>Given</u><u> </u><u>info:</u><u>-</u>If the radius of a right circular cylinder is doubled and height becomes 1/4 of the original height.
Find the ratio of the Curved Surface Areas of the new cylinder to that of the original cylinder ?
<u>Explanation</u><u>:</u><u>-</u>
Let the radius of the right circular cylinder be r units
Let the radius of the right circular cylinder be h units
Curved Surface Area of the original right circular cylinder = 2πrh sq.units ----(i)
If the radius of the right circular cylinder is doubled then the radius of the new cylinder = 2r units
The height of the new right circular cylinder
= (1/4)×h units
⇛ h/4 units
Curved Surface Area of the new cylinder
= 2π(2r)(h/4) sq.units
⇛ 4πrh/4 sq.units
⇛ πrh sq.units --------(ii)
The ratio of the Curved Surface Areas of the new cylinder to that of the original cylinder
⇛ πrh : 2πrh
⇛ πrh / 2πrh
⇛ 1/2
⇛ 1:2
Therefore the ratio = 1:2
The ratio of the Curved Surface Areas of the new cylinder to that of the original cylinder is 1:2
Answer:


Step-by-step explanation:
<u>Quadratic Equation Solving</u>
We have the equation:

Divide by 8:

Now complete the squares so the left side is a perfect square of a binomial:

Factoring the perfect square:

Taking the square root:

The square root of a negative number is an imaginary number:

Solving for x:

The solutions are:


Answer: The answer is 400 blue marbles.
Step-by-step explanation: Given that there are 560 marbles in a bag, out of which 65% are red and rest are blue.
So, number of red marbles is

and number of blue marbles is

Now, if 28 red marbles are replaced by blue marbles, the the new number of red and blue marbles will be

Now, to get 65% of the marbles blue, we need to add some more blue marbles to the bag. Let 'x' number of blue marbles are added to the bag, then

Thus, 400 blue marbles need to be added to the bag.