# Mini Golf Mystery - Using a Protractor

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## Objective

SWBAT use a protractor to create and measure angles to the nearest degree.

#### Big Idea

In this lesson, students create angles on a mini golf course in order to practice using a protractor.

## Warm Up

10 minutes

I begin this warm up by reviewing key angle vocabulary words with students like acute angle, obtuse angle, right angle, degree, and protractor.

Next, I display this smart board interactive protractor and make an angle. -Interactive Protractor

I ask a student volunteer to interact with the protractor and demonstrate how to use the protractor.  This serves as an excellent review for students since they will be using protractors in the concept development portion of the lesson.  If students seem like they need more practice together, I ask another volunteer to explain how to use the protractor with another angle.

## Concept Development

45 minutes

For this lesson, it is important that my students spend time practicing the skill of using a protractor.  My students have had one prior lesson in using protractors prior to this lesson. It was important that I set up a task or experience for students in which they simply weren't just measuring angles in a book or a worksheet. I want my students to see the relevance of angles in their world. I also wanted to use a rich task in order to keep students engaged in this lesson. This time of year, (middle May) many of my students are more interested in counting down the days until their summer vacation, so it is especially important to me that I design and create engaging and meaningful tasks.

I ask my students if they have ever heard that miniature golfers are really great mathematicians?  I then explain to students that when playing miniature golf there is usually some sort of obstruction that blocks the golfer from being able to hit the ball in a straight line from the tee to the hole.  I tell students that usually, a miniature golfer must hit the ball and let it bank (or bounce) off a wall in order to change the direction of the ball and hopefully get a hole in one.   I also tell my students that there are often other things that can affect the balls direction and speed like slopes, and bumps on the the putting green.

Next, I give each student a copy of page 3, 4, 5, and 18 from this angles game sheet -  Angles-Game-Protractor-Golf

I give students directions for their task. First, the object of the game is to draw a single line from the starting point to the hole. The line needs to bounce off walls at the same angle from which it hit the wall like a real golf ball would. (One thing to note is that this lesson also deals quite a bit with reflections. I DO NOT touch on this during the lesson as it is not a fourth grade Common Core State Standard)

I tell students that is will be helpful to begin by estimating which direction and angle they will need to hit the ball to get it in the hole. I tell students they need to use the straight edge of their protractor to draw a straight line from the start point to the first wall the ball would hit. Then they need to use a protractor to measure the angle the ball hit the wall. Then students create that same angle (as a reflection, although I don't use this term with students) the ball would then travel in next.

Students continue the steps above until they have drawn a single line that will result in a hole in one (assuming that there are not hills or dips on the course that would also effect the ball). Students use the three pages (page 3, 4, and 5) writing the angle measurements of each angle for all three holes.  If the hole is missed the player will need to estimate a new direction and try again until they can draw the line to touch the hole.

If time allows, students then use the blank page to create their own miniature golf hole.

## Check for Understanding

5 minutes

For this wrap up, I give each student one angle to measure.  Since students have had several lessons practicing using protractors, it is important to me that I have a full and accurate picture of their skills and deficiencies with using a protractor.

I don't give each student the same angle because I don't want them looking to their learning partner for advice or help for this formative assessments.  Using different angle for every four to five students helps eliminate students wanting to see what degree their learning partner got as an answer.

When I looked at students exit tickets it appears that 21 of my 25 students measured the angle accurately. The other 4 students seem to be confused about the inside and outside numbers on the protractors and which ones to use.  I will touch base with these four students at my re-teaching intervention time and re-teach this skill.  ( I have a 30 minute time slot built into my day, every day, in order to do this. Other students silently read during this time)