OT Trig Puzzle

[Thomas Cole]

Richard,

I'm going to assume that if the circumference of the half circle is 
equal to 10 cm, that means it would be 20 cm if it were a full circle. 
I'm also assuming that the maximum area of the combined figure is when 
the rectangle's sides are of equal length.

Thus, if 3D + piD/2 = 10 cm, then D =  2.1878 cm.

Are you sure this isn't geometry?

Sined,
Tom Cole

Richard Brekne wrote:

>Ok guys and gals... so you think you remember you High School Trig eh ??
>
>Here is a refresher problem
>
>A half circle is placed on top of a rectangle such that its diameter is
>the top side of the rectangle. The length of the 3 remaining sides of
>the rectangle, plus the circumference of the half circle is equal to 10
>cm.
>
>Question: What are the lengths of the sides of the rectangle when the
>area of the combined figure is at its maximum ?
>
>
>... just in case you are bored with your weekend :)
>
>Cheers
>RicB
>
>  
>