Answer:
1. a + b + c = 180
2. b + d = 180
3. d = a + c
Step-by-step explanation:
1. a + b + c = 180:
Angles in a triangle add up to 180
2. b + d = 180:
Angles in a straight line equal 180 because they are supplementary angles
3. d = a + c:
ΔACD is an exterior angle, and ΔACB is interior adjacent, hence ∠a and ∠c add up to ∠d
Answer:
Answer is 9
Step-by-step explanation:
Remember PEMDAS???
"parenthesis, exponents, multiplication, division, addition, subtraction"
you would first solve the addition inside of the parentheses (1 + 2 = 3), and from there finish the equation as it's written from left to right.
