As shown in the figure, during the Golden Week of1/month, Xiaofang saw an arc-shaped door in a tourist attraction. Xiao Fang wanted to know the relevant data of this gate, so he managed it from the sc

As shown in the figure, during the Golden Week of1/month, Xiaofang saw an arc-shaped door in a tourist attraction. Xiao Fang wanted to know the relevant data of this gate, so he managed it from the scenic spot. Solution: cd⊥bd ∵ab⊥bd

∴AB∥CD

AB = CD

∴ABCD is rectangular.

∴AC=BD=200cm,GN=AB=CD=20cm

∴AG=GC= 100cm (3 points)

Let the radius of ⊙O be r, R2=(R-20)2+ 1002, and the solution is R=260cm.

Answer: The radius of this circular door is 260 cm. (7 minutes)