







A hemispherical bowl 
20190429 

From Innocent: Abc is the section through a hemispherical bowl centre O radius 15cm. It contains water whose maximum depth is 8cm. What is the width of the water surface? Answered by Penny Nom. 





Water in a spherical container 
20141017 

From Natalie: A spherical container with radius 10cm being filled with water such that the water level, h cm, in the container increase at a rate of 0.5 cm s^(1). Show that the area of the horizontal surface of water, A cm^(2), in the container is given by A = π(20h  h^(2) ). Answered by Penny Nom. 





Water in a hemispherical bowl 
20120512 

From Jimmy: A bowl of water, being a hemisphere has a radius of 36cm.
Water is filled in the bowl and has depth of 18 cm.
Find the surface area of the water? Answered by Penny Nom. 





Great circle course 
20120125 

From Hervé: On the earth, the mathematical formula giving the distance
between two points, and the initial course for a boat on the great circle
is well known.
I need to find the inverse formula, ie knowing an initial position on earth,
and the initial course of the boat, and the distance to run on the great circle,
the formula gives the final position (longitude and latitude). Answered by Robert Dawson. 





A spherical ball in a conical wine glass 
20111026 

From Jules: A heavy spherical ball is lowered carefully into a full conical wine
glass whose depth is h and whose generating angle (between the axis
and a generator) is w. Show that the greatest overflow occurs when the
radius of the ball is (h*sin(w))/(sin(w)+cos(2w)). Answered by Claude Tardif. 





A triangle on a sphere 
20090907 

From Rohit: How do I find the angles of a triangle drawn on a sphere (spherical triangle)? Answered by Chris Fisher. 





A spherical dome 
20090803 

From Eric: I have recently been asked to resurface a dome sculpture for my local council but i'm having problems working out the area. Here are the dimensions.
The height of the dome is 3m from the ground to the top of the arc. The arc itself from the ground rising up to the 3m point and back down, is 10m. The dome is 7m wide from one side to the other through the centre, at ground level.
I hope there is enough detail here. It's been a long time since i was in a maths class.
Thank you, hope to here from you soon! Answered by Stephen La Rocque. 





A convex quadrilateral in spherical geometry 
20080709 

From Joan: What is the min and max number of obtuse angles possible ia a convex quadrilateral in Spherical Geometry?
I know that the Saccheri has 2 obtuse angles and the Lambert has one, but are there other possibilities?
Thanks for your help. Answered by Chris Fisher. 





A spherical bowl 
20061126 

From Lynne: A spherical bowl of internal radius 15cm is partly filled with liquid. If the radius of the horizontal liquid surface is 12cm, calculate (taking the value of pi to be 3.142), the height of this liquid surface above the center of the bowl. Answered by Penny Nom. 





The volume of water in a sphere shaped water tower 
20060514 

From Dan: I work in the water industry, providing automatic controls for water systems. I was wondering if there was a formula for calculating the volume of water in a sphere shaped water tower? With the use of a pressure gauge we know the elevation of zero water {the bottom of sphere) and the overflow elev. (near the top of sphere) I would like to calculate how many gallons are at any elevation in between. Answered by Stephen La Rocque. 





Noneuclidean geometry 
20031208 

From Geoffrey: How can you use noneuclidean geometry to navigate on a sphere? What geometers did work in this area? Answered by Chris Fisher. 





NonEuclidean geometry 
20031203 

From Geoffrey: What are the applications of NonEuclidean geometry (especially hyperbolic and spherical)? Answered by Walter Whiteley. 





Surface area of a contact lens 
20000606 

From Evie Contreras: I would like to know how to calculate the surface area of a contact lens with a radius of 7mm? I know that the area of a circle is pi R squared, but a contact lens has a dome. Answered by Harley Weston. 





NonEuclidean Geometry 
19990210 

From Robert Smith: Is noneuclidean geometry necessary for the college bound student? I have students that are inerested in teaching math one day. My school is restricted to Euclidean Geometry. Answered by Walter Whiteley and Jack LeSage. 

