Which theorem proves ABC=DCB? Why?
1 answer:
Answer:
Parallel postulate : ALTERNATE INTERIOR ANGLES THEOREM.
Step-by-step explanation:
ALTERNATE INTERIOR ANGLES THEOREM : if a transversal cuts 2 parallel lines, then the alternate interior angles are said to be congruent.
( alternate interior angles : in the given figure, DCB and ABC are alternate interior angles.
ACB and CBD are another pair of alternate interior angles.)
[ theorem is an accepted truth or a verified correct statement already i.e, take protractor and measure it will be same in EVERY case. though i have provided the proof below..]
PROOF: since we know that vertically opposite angles will be congruent, so the angle vertically opposite to DCB will be same as DCB. ( refer attachment for vertically opposite angles) now, as corresponding angles will be congruent (see attachment to know what are corresponding angles), the angle vertically opposite to DCB and ABC are corresponding angles. therefore DCB and ABC are also equal
hence, ABC=DCB.
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Answer:
The options are not given, so i will answer in a general way.
First, we have the system:
y + 2*x = 3
y + 2 = 3*x
To graph this system, the easier way is writing both equations as linear equations, like:
y = -2*x + 3
y = 3*x - 2
Now we just need to graph these two lines in the same coordinate axis.
To do it, we can replace the value of x by two different values in each equation, and see the correspondent value of y for these values. Then graph the two points, and draw a line that connects them.
For example, for the first equation if we have x = 0, we have:
y = -2*0 + 3
y = 3
Then we have the point (0, 3)
and if x = 1
y = -2*1 + 3 = 1
y = 1
we have the point (1, 1)
Now we only need to graph these points, and draw a line that passes through them.
Once we did this for both lines, the graph we will get will look something like the one above.
And the point where the lines intersect is the solution of the system of equations.
Which is the point (1, 1)
