1. vertical, equal to the square of 2.2/a 3.54.10cm5.a6.c7.b8. Prove the triangle ADG congruent triangles ABE(S.A.S) by using the square property.

9. By folding the triangle ABE congruent triangles AFE, then BE=EF, AB=AF and the angle AFE = 90°, because the angle ACB = 45° and EF=FC. So AB+BE=FC+AF=AC.

10. Connect AC, and prove that triangle APC is an equilateral triangle with PC=5 root number 2.