Posted by sophie on Sunday, May 22, 2011 at 2:34pm.
Is it possible for the lengths of a right triangle to form a geometric sequence? If yes, determine the lengths and the measures of the acute angles. if it's not possible, explain why not.

math  bobpursley, Sunday, May 22, 2011 at 3:21pm
lengths of a right triangle? You mean the three sides?
Try it: lengths a, ar, ar^2
now see if Pythagoras postulate will work:
c^2=a^2 + b^2
Either a, or ar^2 is c. Try a first
a^2=(ar)^2+(ar^2)^2
dividing by a^2
1=r^2 + r^4
r^4+r^21=0
r^2 = (1+sqrt(5))/2
r= 1.272
so sides are a; 1.272a; 1.618a
which means a was not the longest side.
check:
(1.618^2)=1^2+1.272^2
acute angles?
sinA= 1.272/1.618 Then B: sinB=1/1.618