Complete the statements to find the measurements of ∠a and ∠b .

Answer:
∠a=80
∠b=50
Step-by-step explanation:
∠a and 100 are on a straight line. Therefore they are supplementary, and add to 180 degrees. So, we can say that:
∠a+100=180
To solve, subtract 100 from both sides. This will leave ∠a by itself.
∠a +100-100=180-100
∠a=80
The angles in a triangle must add to 180 degrees. Therefore,
∠a + ∠b + 50= 180
We know ∠a is 80, so we can substitute that in
80+ ∠b +50 =180
∠b+80+50=180
Combine like terms
∠b+(80+50)=180
∠b+130=180
To solve, subtract 130 from both sides. This will leave ∠b by itself.
∠b+130-130=180-130
∠b=50
Answer:
∠a = 80° and ∠b = 50°
Step-by-step explanation:
Look at angle a. Angle a and 100 both lie on the same line, which means they are supplementary and add up to 180. Then we can write: m∠a + 100 = 180. To solve this for a, we simply subtract 100 from both sides:
m∠a = 80°
Now, look at the triangle. All the angles in a triangle add up to 180, so we have the equation: m∠b + 80 + 50 = 180. Solve for b by subtracting 80 and 50 from both sides: m∠b = 50°.
Thus, ∠a = 80° and ∠b = 50°.