First you need to know the definition of a complementary angle. That means that two angles add up to 90 degrees, or a right angle.
To find an angle complementary to a 78 degree angle, you need to subtract 78 from 90.
90 - 78 = 12
Let the number be x
Equation:
12 + 5x = -3
Answer: The equation is 12 + 5x = -3
Solve it:
5x = -3 - 12
5x = -15
x = -15 ÷ 5
x = -3
Answer: The number is -3.
<span>2² + 4² ÷ 2<span>²
4 + 16 </span></span>÷ 4
4 + 4
8
