2 questions! area of plane and composite figures

Me with geometry ! in this figure, bc is a perpendicular bisects of kj. dm is the angle bisects of bdj. what is the measure of bdm? •60° •90° •30° •45°

1) prove that 731^3−631^3 is divisible by 100 2) prove that 99^3−74^3 is divisible by 25

Change negative exponents to positive. then solve. round to four decimal places