



 
Hi Kate, Look at my diagram The lengths a and b are given as is the measure of the angle at A. There are two possible configurations, triangle ABC and AB_{1}C. In fact the measure of the angle B_{1} is 180^{o} minus the measure of the angle B. From the diagram sin(B) = h/a and hence sin(B)/b = h/(ab). But by the law of sines sin(B)/b = sin(A)/a and hence
and thus
Thus if h < a then b sin(A) < a. You have A as 36 degrees and sin(36) is positive so b < a/sin(A) = 5/sin(36). I hope this helps,  


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