<PRE><B>Question 175296</B>
A rectangle is composed of 4 right angles. With the diagonal you have created two triangles and better yet 2 right triangles. You would then use the pythagorean therom a^2+b^2=c^2

you already have the value for c=61 and a=11 all you have to do is plug in the numbers

121 +b^2=3721

subract 121 from both sides 

b^2=3600
b=60

Let us doublecheck

121+3600=3721

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