How to create this specific curve?

Hi! For our architecture project, we’ve been asked to use parametrisation on Grasshopper as a tool to define the shape of our pavilion roof. For the right side of the roof, we’ve already managed to parameterize the two straight line segments (c.f. the pink lines on the first picture and the second picture for the screenshot of our “code”). But we’d like our shape to be continuous (with the yellow curves), and the green arc to have a variable “radius”. And we just started exploring Grasshopper, so we don’t really know how to do it by ourselves… Would you have any tips or hints to help us figure this problem out?
Thank you very much! !