Question 22
Triangle ABC is isosceles at B, with angles BAC=ACB=30°. Points D1,D3,D5,...,D9 lie on AC and D2,D4,...,D8 lie on BC, with AD1=AB, BD2=BD1, D1D3=D1D2, D2D4=D2D3,...,D7D9=D7D8, forming ten small triangles as shown. What is their largest interior angle?
