Problem 11
Answer: Angle C and angle F
Explanation: Angle C and the 80 degree angle are vertical angles. Vertical angles are always congruent. Angle F is equal to angle C because they are alternate interior angles.
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Problem 12
Answer: 100 degrees
Explanation: Solve the equation E+F = 180, where F = 80 found earlier above. You should get E = 100.
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Problem 13
Answer: 80 degrees
Explanation: This was mentioned earlier in problem 11.
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Problem 14
Answers: complement = 50, supplement = 140
Explanation: Complementary angles always add to 90. Supplementary angles always add to 180. An example of supplementary angles are angles E and F forming a straight line angle.
Answer:

Step-by-step explanation:

Answer:
The speed of the boat is 20 km/hr
Step-by-step explanation:
Let s be the speed of boat in still water
Let d be the distance
Upstream speed = s-4
Jane took 30 min to drive her boat upstream to water-ski at her favorite spot.
So, Distance traveled in upstream =
Downstream speed = s+4
So, Distance traveled in downstream = 
So, 
30s-120=20s+80
10s=200
s=20
Hence The speed of the boat is 20 km/hr
<u><em>Answer: B. m=-23 and -23=m. *The answer should be the negative sign.*</em></u>
Step-by-step explanation:
addition property of equality is adding the same number to both sides of an equation does not change the equation.
a+c=b+c
add by 10 both sides of equation.
m-10+10=-33+10
simplify.
33-10=23
23+10=33
33-23=10
m=-23
It changes positive to negative.
Hope this helps!
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