Mensuration

Jai Ganesh · 2015-12-31 14:42:43

Hi Relentless and bobbym,

M#170. The radius of a solid sphere is 24 cm. It is melted and drawn into a long wire of uniform cross-section. Find the length of the wire if its radius is 1.2 mm.

Relentless · 2015-12-31 15:01:55

Hi ganesh,
The question M#169 originally stated that the base area of the cone was 12 (I assume square centimetres), not the radius.

bobbym · 2015-12-31 16:52:00

Hi;

Relentless · 2015-12-31 17:24:01

Hi bobbym
I noticed that you used the same formula, but taking pi to be 22/7
Happy New Year!

Jai Ganesh · 2015-12-31 17:27:37

Hi bobbym,

The solution M#170 is perfect! Excellent!

New Year Wishes, bobbym!

M#171. Through a cylindrical pipe, of internal radius 7 cm, water flows out at the rate of 5 cm/second. Calculate the volume of water (in liters) discharged through the pipe in half an hour.

bobbym · 2015-12-31 18:11:49

Hi;

Hi Relentless;

I always use pi = 22 / 7 when doing these problems.

Relentless · 2016-01-01 00:50:22

Hello!

Hey bobbym,
It's a good approximation. For example, for this problem, the error is only about 560mL, or about 725 milliseconds worth of water.
But for some reason, I just don't like using approximations when an exact answer is within reach xS

Last edited by Relentless (2016-01-01 00:54:15)

Jai Ganesh · 2016-01-01 02:46:30

Hi bobbym and Relentless,

The solution M#171 is perfect! Brilliant!

M#172. Water in a cylindrical tank of diameter 4 meters and height 10 m is released through a cylindrical pipe of diameter 10 cm at the rate of 2.5 km / hour. How much time will it take to empty the half of the tank? Assume that the tank is full of water to begin with.

Relentless · 2016-01-01 03:16:50

Hello!

bobbym · 2016-01-01 07:12:10

Hi;

Jai Ganesh · 2016-01-01 15:43:22

Hi Relentless and bobbym,

The solution M#172 is perfect! Excellent, Relentless and bobbym!

M#173. Spherical shaped marbles of diameter 1.4 cm, are dropped into a cylindrical beaker of diameter 7 cm containing some water. Find the number of marbles that should be dropped into the beaker so that the water level rises by 3.6 cm.

bobbym · 2016-01-01 19:18:31

Hi;

Relentless · 2016-01-01 20:07:14

Hi!

My answer agrees with yours bobbym, even though it is a strange result for this kind of problem P:

Last edited by Relentless (2016-01-01 20:07:56)

Jai Ganesh · 2016-01-02 00:10:12

Hi bobbym and Relentless,

The solution M#173 is perfect! Excellent!

The problem ought to have been:
Spherical shaped marbles of diameter 1.4 cm, are dropped into a cylindrical beaker of diameter 7 cm containing some water. Find the number of marbles that should be dropped into the beaker so that the water level rises by 5.6 cm.

and the solution : 150.

M#174. A cup is in the form of a hemisphere surmounted by a cylinder. The height of the cylindrical portion is 8 cm and the total height of the cup is 11.5 cm. Find the total surface area of the cup.

bobbym · 2016-01-02 06:07:05

Hi;

Jai Ganesh · 2016-04-01 01:34:27

Hi;

M#175. The radii of two circles are 19 cm and 9 cm respectively. Find the radius of the circle which has circumference equal to the sum of the circumferences of the two circles.

M#176. A wheel of a cart is making 4 revolutions per second. If the diameter of the wheel is 84 cm, find the speed of the wheel in centimeters per second.

bobbym · 2016-04-01 15:13:05

Hi;

Jai Ganesh · 2016-04-01 15:46:12

Hi;

The solution M#175 is correct. Well done!

Now, solve M#176, bobbym!

bobbym · 2016-04-01 15:50:21

Hi;

Jai Ganesh · 2016-04-01 16:46:14

Hi;

The solution M#176 is perfect. Excellent, bobbym!

M#177. The sum of radii of two circles is 140 cm and the difference of their circumferences is 88 cm. Find the diameters of the circles.

bobbym · 2016-04-01 19:01:21

Hi;

Jai Ganesh · 2016-04-01 23:05:46

Hi;

The two solutions in M#177 are correct. Good work, bobbym!

M#178. If the perimeter of a semicircular protractor is 36 cm, find the diameter of the protractor.

.

bobbym · 2016-04-02 00:17:09

Hi;

Jai Ganesh · 2016-04-02 17:11:12

Hi;

The solution M#178 is correct. Neat work, bobbym!

M#179. A boy is cycling such that the wheels of the cycle are making 140 revolution per minute. If the diameter of the wheel is 60 cm, calculate the speed per hour at which the boy is cycling.

bobbym · 2016-04-03 01:45:32

Hi;

Math Is Fun Forum

#376 2015-12-31 14:42:43

Re: Mensuration

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