A B and C are points on the circumference of a circle. XY is a tangent to the circle at the point A. Angle BAY=72 and angle ABC=54.

Prove that triangle ABC is an isosceles triangle.
You must give a reason for any statement or any calculation you carry out.

( do not answer if you don't know the answer, thank you.)

Bo is buying a board game that usually costs bb dollars. the game is on sale, and the price has been reduced by 18\%18%. which of the following expressions could represent how much bo pays for the game? choose 2 answers: choose 2 answers: (choice a) a 0.82b0.82b (choice b) b 1.18b1.18b (choice c) c b-0.18b−0.18 (choice d) d b-18b−18 (choice e) e b-0.18bb−0.18b