The door stop

A triangle with a cevian. What is α?

Scroll down for a solution to this problem.


The angle α is 15°.

Solution by Bob Ruyle.


The door stop
A device to hold your door
A gadget
A door stopper
It can be so cute
Like this small iron bear
It can be heavy
It can be light
Made of iron
Or may be of wood
Or even in needlepoint
Filled with flowers
For our young pets
Easy to install
And doing so good


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2 replies on “The door stop”

Is there any good geometrical interpretation for the other two positive values of sin(x) for which sin(4x)/sin(3x)= sqrt(3/2)?

Oops. I made a sign error. The only other solution to sin(4x)/sin(3x) = sqrt(3/2) that I found is x = 75 degrees. But that would make 3x = 225 degrees.

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