On a given line, (on one side) there are a total of 180°
if one line in Problem #3 is bisected by a line, with one half X and the other 120°,
do 180° (the total) minus 120° which=60°
now the hard part, that line that bisected the first line is bisecting a line that is parallel to your second line, the one with <5 and <6
this means that the big angle formed in the first one with 120° is the same angle as in the second line, leaving <5 as 120°
which means <6 is 60°, like in the top part of the problem. You're basically flipping the top line upside down, I hope it helps.
Y =ax² + bx +c
1) Point (0,7)
7 = a*0² +b*0 +c
c = 7
y=ax² + bx + 7
2) Point (1,4)
4=a*1² + b*1 + 7, ----> 4 = a +b + 7, ------>
a+b= - 3
3) Point (2, 5)
5=a*2² + b*2 + 7, ----> 5=4a+2b +7,---> -2=4a+2b, ---->
-1=2a + b
4)
a+b= - 3, ----> b= -3 - a (substitute in the second equation)
2a+b= -1
2a - 3 - a = -1, ----> a - 3 = -1,
a =2
5) a+b= - 3
2 + b = -3
b = -5
y=2x² - 5x + 7
Conjecture
is an educated guess based on known information. Reached by using inductive reasoning
angle AOB = 132 and is also the sum of angles AOD and
DOB. Hence
angle AOD + angle DOB = 132° ---> 1
angle COD = 141 and is also the sum of angles COB and BOD. Hence
angle COB + angle DOB = 141° ---> 2
Now we add the left sides together and the right sides of equations 1 and 2
together to form a new equation.
angle AOD + angle DOB + angle COB + angle DOB = 132 + 141 ---> 3
We should also note that:
angle AOD + angle DOB + angle COB = 180°
Therefore substituting angle AOD + angle DOB + angle COB in equation 3 by 180
and solving for angle DOB:
180 + angle DOB = 132 + 141
angle DOB = 273 - 180 = 93°
3,000,000+28,000+2=3,028,002
