Cogito
Geometry · Chapter 7 · Lesson 3
Proving Things with Coordinates
Turning a geometric claim into arithmetic.
11 problems · about 23 minutes · G-GPE.B.4, G-GPE.B.5
Figure — use these to answer the problems
Warm Up
Straightforward practice. Get the method working first.
4 problemsFrom (2, 1) to (6, 4). Distance?
AnswerFrom (1, 2) to (4, 6). Distance?
AnswerMidpoint of (2, 4) and (8, 10). What is its y?
AnswerSlopes 3 and 3. Parallel? 1 for yes, 0 for no.
Answer
Build It Up
The same ideas with more to keep track of.
3 problemsSlopes 2 and −0.5. Perpendicular? 1 for yes, 0 for no.
AnswerMatch each claim to the tool that settles it.
Draw a line from each item on the left to its match on the right.
- These sides are equal
- These sides are parallel
- This point bisects the segment
- Distance formula
- Slope
- Midpoint formula
From (0, 0) to (5, 12). Distance?
Answer
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
4 problemsDoes using letters instead of numbers make a proof general? 1 for yes, 0 for no.
AnswerMidpoint of (−4, 0) and (4, 0). What is its x?
AnswerThe Distance
From (0, 0) to (3, 4). Distance?
AnswerThe Midpoint
Midpoint of (0, 0) and (8, 4). What is its x?
Answer