Math Forum / Mathematics / Algebra Help / December 2007

Is it correct that the formula to calculate the surface of a
sphere(ball) is: 4 x pi x (R x R).?
thanks

Riding the subway home on the last leg of our return from the Staten
Island Zoo yesterday, my seven year old son Dan asked me to do the
following (Dan doesn't know much terminology, so I'm including it
parenthetically):

Dear Student,
1.
I hold B.Tech. engineering degree from IIT  Kanpur and I have 20 years
experience of classroom face-to-face teaching of Mathematics and

It is a multiple answer question.
Three soldiers washed 98 windows of the barracks.  Two of the soldiers
washed the same number of windows.  The third soldier washed 5 more
windows than either of the other soldiers.  How many windows were

In ``Calculus'' by James Stewart, 4th edition, chapter 11, section 1 (if
I recall correctly), there's the argument that the pair of equations
above describes a circle because ~``we can eliminate t by noticing that
                 x^2 + y^2 = cos^2(t) + sin^2(t) = 1;