r? =﹙0.72÷2﹚? ﹢﹙R-0.25﹚?
r? =0. 1296+R? -0.5R+0.0625
R ≈ 0.384 (m)
Let the radius of this tire be r meters.
4. Solution: CD=CE
Proof: connecting OC,
∫ Arc AC= Arc BC
∴∠DOC=∠EOC
And e are the midpoint of radii OA and OB, respectively.
∴OE=OD
OC = OC reappears.
∴△OCD≌△OCE(SSS)
∴CD=CE (the corresponding sides of congruent triangles are equal)