Question

If the angles ( 2a - 10 )° and ( a - 11 )° are complementary, what is the value of 'a'.

Answer 1

(2a -10)+(a - 11)= 90           (sum of complementary angles= 90)
2a - 10 + a - 11=90
3a -21= 90
3a= 90+21
3a =111
a= 111/3
a = 37

Answer 2

sum of complementary angles is 90 degree
therefore,
(2a-10)+(a-11)=90
(bring like terms together)
(2a+a)-(10+11)=90
3a-21=90
3a=90+21=111
a=111÷3
a=37