Problem: the points a ( 0 , 0 ) , b ( 0 , 4 a - 5 ) and c ( 2 a + 1 , 2 a + 5 ) form a triangle . if angle abc = 90 , what is the area of triangle abc ? 
Options: a ) 80 , b ) 82.5 , c ) 78.5 , d ) 75.5 , e ) 74
b