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Linear Pairs of Angles
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EEVblog:
So 8yo Sagan get these questions in his extension math class.
And I'm like  :-//

StillTrying:
B2 is
180/2 +/- 24/2  =  90 +/- 12  =  102 and  78

The second B2 is the same working 90 +/- 21

The images are tooo big.

Brumby:
"Linear pairs" ? ? ?  When I was in school they were called supplementary angles.

The English used to describe the actual question in B(1) on sheet 2 isn't all that clear to me.  Seeing the answer makes it obvious, but the phrase used isn't how I would expect such an idea to be presented.  Maybe I just need to spend some time in class and get used to the "new speak".

I am a little surprised at these questions thrown at an 8 y.o. as a couple of them lean into algebraic processes.
bsudbrink:
Here's what I see:

To solve Sheet 2, B2, it is clearest to use simultaneous equations:

a+b=180  given by "In a linear pair of angles"
a+24=b    given by"one angle measures 24 more than the other"

a+a+24=180  substitute  a+24 for b
2a=156          subtract 24 from both sides and combine a
a=78              divide both sides by 2
b=102            subtract 78 from 180

To solve Sheet 1, B2, same method as Sheet 2, B2:

a+b=180   given by "a linear pair of angles"
a-b=42      given by "the difference" ... "is 42"
a=b+42    add b to both sides

b+42+b=180  substitute b+42 for a
2b=138          subtract 42 from both sides and combine b
b=69              divide both sides by 2
a=111            subtract 69 from 180

I assume the red mark on Sheet 1, B3 indicates that the instructor thinks there is an error...
It looks correct to me.  Maybe the instructor is being a stickler about the order???

mrflibble:
For a short & clear definition, see http://www.mathwords.com/l/linear_pair_of_angles.htm

For the longer version, see: https://en.wikipedia.org/wiki/Angle#Combining_angle_pairs

Two angles that sum to a straight angle (1/2 turn, 180°, or π radians) are called supplementary angles.

If the two supplementary angles are adjacent (i.e. have a common vertex and share just one side), their non-shared sides form a straight line. Such angles are called a linear pair of angles.
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