Answers:
Choice 2) Angle ABC is bisected by ray BD.
Choice 3) BC = 1/2 AC
Choice 5) 2*(angle DBC) = angle ABC
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Explanation:
Since B is the midpoint of AC, this means that AC is cut in half to form the smaller equal pieces AB and BC
We can then say
AB+BC = AC
BC+BC = AC
2BC = AC
BC = (1/2)*AC
which shows why choice 3 is one of the answers
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Angle ABD is shown to be 90 degrees. Let's say we didn't know angle DBC is also 90. Lets call it x
(angle ABD) + (angle DBC) = 180
90 + x = 180
x = 180 - 90
x = 90
So angle DBC is also 90.
We can see that the 180 degree angle (ABC) is cut in half into two smaller 90 degree angles (ABD and DBC). Therefore, angle ABC has been cut in half and that's why choice 2 is another answer.
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Using the angle addition postulate, we know that,
(angle ABD) + (angle DBC) = angle ABC
(angle DBC) + (angle DBC) = angle ABC
2*(angle DBC) = angle ABC
Showing why choice 5 is the third answer.
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Choice 1 isn't true since ray BD helps form angle DBC.
Choice 4 isn't true because there isn't a tickmark on segment BD to indicate it's the same length as BC.
