These triangles are similar. Find?

The center of the circumscribed circle lies on line segment and the longest side of the triangle is equal to the of the circle.

Can some one explain this i got sent this. is this a threat i’m scared

Jessica is organizing a guided tour of the rain forest. the average profit per person that the touring company makes is given by the rational expression 18x+35/x, where x is the number of people going on the tour. what does the numerator of this rational expression represents?