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Post a message or simply read what others have written and answered. Rachel, a RightStart™ Math user and one of our customer care people, will be monitoring this forum. She will respond to your questions as needed.

Have a great day and remember to play a math card game! 


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Re: Geometry Lesson 69

Hi, Roxane. My name is Rachel and I am happy to help you today.

Thank you for your post. In this activity, you will learn how to use the mm-arc compass. It is important that your child learns how to use the arc, so it can be used in the future. So, you do not want to skip that part of the lesson.

The first step when making the arc is to draw parallel lines on either side of where the arc is to be. For example, in Problem 1, you will need to draw a vertical line down from the top line and a horizontal line off the left line. Be sure to start your line where the top and side lines stop. Where those lines intersect (or cross) will be the place where you put the center of the mm-arc compass. Line up the mm-arc compass and choose an arc distance that will connect both the top line and the left side line.

This is an odd kinda of lesson for me to try to explain in words. ;-) So, if you are still not sure, please feel free to email me directly at I will be happy to provide step-by-step picture instructions so you can see how it is done.

I hope that helps! As always, please feel free to post any further questions you may have or email us directly at

Have a fabulous summer!

Re: Geometry Lesson 69

Hi, Roxane. This is Rachel again. ;-)

One thing I was going to include in the last post, but forgot, was the radius measurements (from the mm-arc compass).

For problem number 1, the radius is measured 1.1 cm. Then for number 2, the radius on the very top is measured 1.5 cm and the two on the side is measured at 1 cm. Finally, on number 3 the radius for the large rectangle is 1 cm and for the pentagon it is 1.3 cm.

I hope that helps!
Have a wonderful day!

Re: Geometry Lesson 69

Thank you! We are going to re-visit this tomorrow.