







tan15° 
20160411 

From JOHN: find the exact value of tan15° in surd form. Answered by Penny Nom. 





The derivative of y = sin (30º + x) 
20121107 

From Saskia: derivative of y = sin (30º + x) Answered by Harley Weston. 





Angle measures 
20120321 

From jogiboy: how can i get the sine theta if the given is 3.14/3 Answered by Penny Nom. 





The rate of change of the area of a parallelogram 
20110405 

From Gevork: Let a parallelogram have sides of 8 and 12 and let vertex angle A be decreasing at a rate of 2degrees per minute. Find the rate of change of the area of the parallelogram when angle A equals 30 degrees. Answered by Penny Nom. 





A cylinder is cut at an angle of 20 degrees 
20100125 

From sanjay: If I have a cylinder with 40mm diameter and I will cut it at an angle
20 degrees so what would be the increased radius or dia.??? of the cylinder Answered by Penny Nom. 





The sum of the angles of a triangle 
20090518 

From mary: prove that the sum of the three angles inside any triangle always add up to 180 degrees? Answered by Harley Weston. 





How many feet does a shadow move per hour? 
20090402 

From Zora: How many feet does a shadow move per hour? Answered by Robert Dawson. 





limit sinx/x 
20090130 

From Jackie: how to evaluate limit sinx/x as x tends to zero if x is in degrees Answered by Stephen La Rocque and Harley Weston. 





1 foot drop every 25 feet 
20090122 

From jerry: 1 foot drop every 25 feet what is the angle of the degree Answered by Penny Nom. 





What angle should he turn? 
20071201 

From Jasmine: Bob is traveling due north he then turns left 45 degrees followed by four 20 degree turns to the right
What is his new heading if he needed to turn so his heading was SSW what direction and what angle should he turn? Answered by Walter Whiteley. 





Is there a practical use for radian measure? 
20071026 

From Paula: Is there a practical use for radian measure in any profession? Which professions might us radian as opposed to degree measure? Answered by Harley Weston. 





Angle of clock hands 
20070131 

From Sophia: How many degrees are in the aute angle formed by the hands of a clock at 2:20 p.m.? Answered by Stephen La Rocque. 





Fahrenheit and Celsius 
20060612 

From Doris: I just know how to do problems with fahrenheit or celcius. Could you show me step by step how to do these? Then I can do it if you can show me each step of the way. Answered by Stephen La Rocque and Penny Nom. 





Degrees and grads 
20060406 

From Nazanin: which angle if you add 15 to its degree we can find its measure by grad? Answered by Stephen La Rocque. 





Cosine of 35 degrees 
20040303 

From Jason: How do you find the exact solution to cosine 35 degrees. Answered by Chris Fisher. 





Radians 
20030116 

From Erikson: I am a student in the 10th grade and attending advanced math at my high school. I was assign to do a report about the unit circle and the radian. But there seems to be no information available about the history of the radian; who first found out about them, which civilizations used it if any. Well, hopefully you'll assist me in this troubling question. Thank you for your kind consideration. Answered by Penny Nom. 





Radian measure 
20010726 

From Amy: i have to find out what is meant by the radian measure of an angle and compare it to the measure of an angle in degrees. Answered by Harley Weston. 





Law of cosines 
20010220 

From Emily: I missed a few days of class and I can't figure out how to solve Law of Cosines problems. I have the notes and formulas but I can't figure out how to do the math involved to answer the problems. I am also getting confused about how to use degrees and seconds in the Law of Sine and Cosine. I can't seem to get the correct answers and I don't really know how to solve them and enter them into my TI 86. Answered by Harley Weston. 





Motivators 
20010116 

From Michelle Stapley: Do you know of any (or where I can find) student motivators for math at the secondary level? Basically any way I can motivate my students to WANT to learn math. Answered by Penny Nom. 





The side length ratios of some triangles 
20000404 

From Alexis Lockwood: I am doing a project for my Math 30B class regarding the side length ratios of 454590 degree and 306090 degree triangles. I would really appreciate any assistance in answering the following questions, or even direction to an appropriate web site or resource on the matter. Answered by Harley Weston. 





Specific heat 
19991222 

From Irena: In transferring 1260J of heat to water, the temperature of 0.20 kg of mercury falls 50 K. Calculate the specific heat capacity of mercury using the equation C= Q/(m)(delta t) i know that Q= 1260J because it's loosing heat and m= 0.2kg and since i have to use 'C i have to convert Kelvins into Celsius (i also know that 'C has to be negative since it looses heat) . . . Answered by Harley Weston. 





Degrees and triangles 
19990909 

From Sandra Mills: Are there any triangles which are not 180 degrees? I am also in need of information on the history of degree measure for an angle. Answered by Walter Whiteley. 





The sum of the angles of a triangle is 180 degrees 
19980219 

From Quin Liu: How do you prove that the sum of the angles of a triangle is 180 degrees? Is there a proof? what is it? Answered by Chris Fisher. 





Trigonometric functions 
19971221 

From Calvin Cheng: My name is Calvin and I have a year 12 question for you to help me with. From a point S, the angle of elevation of the top of a tower due north of it is 20 degrees. From R, due east of the tower, the angle of elevation is 18 degrees. S and R are 100m apart. Find the height of the tower. Answered by Harley Weston. 





Why is a circle divided into 360 degrees? 
19960930 

From Kurtis Kredo: I was recently wondering why a circle has been divided in to 360 degrees. When I asked my physics teacher he could not think of an answer. His guess is that it probably has to do with people long ago using the base 6 number system. I have a small inkling that it has to do with easy conversion or usage with radians or grads. Answered by Chris Fisher. 

