Answer:
12 3/4 same slope fro both
13 DE = 5, CB = 10
14 see below
Step-by-step explanation:
12. the slopes are the same
D(0, 3) E(4, 6) slope is (change in y)/(change in x)
change in y = 3 to 6 is a change of +3
Change in x = 0 to 4 is a change of +4
slope is 3/4
13 To fine lengths you can distance formula or Pythagorean theorem (spoiler: they are related to each other)
DE² = 3² + 4²
DE² = 9 + 12
DE² = 25
√DE² = √25 = 5
DE = 5
and
CB² = 6² + 8²
CB² = 36 + 64
CB² = 100
√CB² = √100 = 10
CB = 10
14. since the slopes are the same are DE is 1/2 or CB its is the mid segment. because (taken from mathopenref.com/trianglemidsegment.html)
The midsegment is always parallel to the third side of the triangle. In the figure above, drag any point around and convince yourself that this is always true.
The midsegment is always half the length of the third side. In the figure above, drag point A around. Notice the midsegment length never changes because the side BC never changes.
A triangle has three possible midsegments, depending on which pair of sides is initially joined.
