Hello

i was wondering if you geometry gurus can help me out

if you look at this

Long compass

can you tell me if there is name for this

and can you also help me to formulate a formula to allow me to generate the radius from the angle of the two sticks and the distance of the pins

i am hoping to use this type of movement to cut large radius in plywood

say from 8ft to 75 ft radius over the long side of a sheet of ply

we build concrete skateparks and use large radiuses all over the place

thanks

Bryant