The measure of the angle is 6°
A complementary angle consists of two angles who's sum is 90 degrees. Since there are two we know this for sure:
1st angle: x (unknown value)
2nd angle: x-78 (78 less then its complement)
total: 90
If we put the equation together we get: x+x-78= 90
x+x-78+78=90+78
2x=168
2x/2=168/2
x=84
Now we know that x = 84, know we gonna find the 2nd angle:
1st: x=84
2nd: 84-78 = 6
total: 84+6=90
