The document is a teacher's lesson plan for a geometry class that includes the following: 1) An agenda for the day covering lesson 4.1 on midpoints and detours and an exit slip. 2) Learning objectives for lesson 4.1 which are to calculate midpoints using the midpoint formula and use detours in proofs. 3) An example of using the midpoint formula to find the coordinate of a midpoint on a number line.

1. Geom4­1.notebook November 01, 2011
BELL WORK:
State ALWAYS, SOMETIMES, or NEVER:
1. A median is an altitude.
2. A right triangle is congruent to an equilateral triangle.
Agenda for the day:
• 4.1
• exit slip
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2. Geom4­1.notebook November 01, 2011
4.1 ­ Midpoints and Detours
After this lesson, you should be able to:
1. Calculate the location of a midpoint using the midpoint formula.
2. Use detours in proofs.
On the number line to the right, A M B
determine the coordinate for M 2 14
if M is the midpoint of AB:
The Midpoint Formula:
Sometimes it is necessary to prove more than
one pair of triangles congruent in order to
reach a conclusion.
We call such proofs detour proofs.
Let's look at the example on p.169.
Extra examples: see the sample problems on pp.171 and 172
The procedure for detour proofs is on p.170
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3. Geom4­1.notebook November 01, 2011
Detour proof: p.173 #2
M
Q
P N
Given:
S
Prove:
Exit Slip: p.172 #1
You don't have to write the entire proof, just
number 3­7 and fill in the blanks.
Homework: 4.1 Practice Worksheet
due Thursday
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