







The top half of a cone 
20190227 

From danica: What portion of the height from top that the cone be cut into two equal volume? Answered by Penny Nom. 





A deck that is half an ellipse 
20160228 

From Steve: On your website, I was reading a question and your response from a girl named Angela in which you provided a formula by which her father, a welder, could figure out points on an arc corresponding to equal 3' intervals on a 30' chord where the vertex was 1' off the chord. Is there an equivalent formula when working with an ellipse? I suspect this change will make the calculations significantly more complex. I am building a deck that is half an oval, and would like to be able to mark out the perimeter by measuring the distance from regular intervals on the primary access to a corresponding point on the perimeter. I will then connect the points on the perimeter and cut a reasonably smooth arc. The length of the primary access will be 22' and width of the deck at the vertex is 9'. I would like to be able to know the distance from the primary axis to a point on the perimeter at equal intervals of 6" along the primary axis. Can you help? Answered by Penny Nom. 





A wireless fence 
20150418 

From Dave: I'm buying a wireless fence to keep my pet in my yard. It has a half acre range. In a straight line how far would that be? Answered by Penny Nom. 





More than half of the people said... 
20130826 

From Lucy: Hi,
The question is:
Samoa 23%
Brazil 41%
Sri Lanka 52%
Senegal 39%
Armenia 37%
Croatia 20%
Why is the following statement true for the data above: More than half of the people said they were interested in Sri Lanka. The reason I don't understand the problem is that because the percentages add up to be greater than 100%, that means that the 500 people(as stated in the question) who participated in the survey got to pick more than once. Therefore, it is not 52% out of 100% anymore.
Thanks for taking the time to answer my question. Answered by Robert Dawson. 





Expressing 0.5% 
20120206 

From Kenneth: Hello:
It is correct to express 0.5% as 5 tenths of one percent.
Is it also correct to express 0.5% as 5 tenths of onehundred percentage points or 5 tenths of one percentage point?
I think it would be 5 tenths of one percentage point because 5 tenths of onehundred percentage points would be 50 percentage points, but I'm not sure.
I thank you for your reply. Answered by Penny Nom. 





0.5 acres of land 
20111109 

From Kim: I have .5 acres of land. I want to divide it into 20x20 squares. How many squares will I have? Answered by Penny Nom. 





The top half of a cone vs. the bottom half of the same cone 
20090108 

From Tammy: What is the ratio of the volume of the top half of a cone vs. the bottom half of the same cone? Is it seven times larger, or four times larger? and is the ratio consistent regardless of the size of the cone opening? Answered by Penny Nom. 





Half life 
20080929 

From aisyah: if dA/dt = kA
and A(0) = A as the model for the decay of a radioactive substance,
how can show that in general, the half life T of substance is T = (In 2)/k Answered by Harley Weston. 





Half a circle 
20080904 

From brandon: what are the area and perimeter and area of half a circle?? Answered by Penny Nom. 





The perimeter of a half acre square 
20080420 

From s: Measured in feet. What would be the perimeter of a square area of land measuring
1/2 acre? Answered by Penny Nom. 





Time and a half 
20080301 

From Travis: Bill receives time and a half for working overtime. If Bill is paid $55 for each hour of overtime, how much is his regular hourly wage? Answered by Stephen La Rocque. 





Rays 
20060831 

From Natasha and daughter: My daughter, Natasha, is in 4th grade. She had the following homework question about rays that confused us:
Name as many rays as you can in the figure below. Answered by Penny Nom. 





The lower half of a sphere 
20060830 

From Yvette: I am interested in finding out how to represent the lower half of a sphere in the form of z=f(x,y) with r=2 and a centre point (3,1). Answered by Stephen La Rocque and Penny Nom. 





Half of five 
20041226 

From Pauline: Why is four half of Five? Hint: It's the middle half? Answered by Penny Nom. 





Half way between 
20040908 

From Ben: Find the number halfway between the number shown
751,843 Answered by Penny Nom. 





The halfway mark 
19990420 

From Sherry & Tom McGee: How do you figure the halfway mark between 1/3 and 2/3 as a fraction and a decimal point? Answered by Penny Nom. 

