≈c = 90 ac⊥af
∴△ABC and△△△ APQ are right triangles.
HL theorem can be used to prove the congruence of two right triangles.
PQ = AB
Point p has moved for 2.5 seconds, that is, CP=5cm.
AC = 8cm,BC=3cm。
∴AP=BC=3cm
∴△ABC≌△APQ(HL)。