## The Geometer's Sketchpad Intro Lab Assessment

### Mike Riedy

This quest - halfway between a quiz and a test - covers materials learned in the GSP Introductory Lab, plus an optional section related to the Spirograph activity.

#### Part I: Preliminary Setup

This quest is all about using GSP and following directions. You must read carefully; if you don't, you may miss something very small but important. When you are told to print something, make sure your name is on the screen before you print it so your work won't be confused with someone else's.

Your measurements must be consistent with everyone else's, so set your "Preferences" to measure distance units in centimeters with a precision of thousandths. Measure the angles in degrees, also with a precision of thousandths. You may use the GSP Introductory Lab as a reference.

#### Part 2: Following Directions

You will be making a sketch by following directions. Open the Geometer's Sketchpad. You should have a "New Sketch" - if you don't, get one.

Draw a horizontal line. "Hide" the two points on the line. Put two "Points on Object". Rename the point on the left A and the point on the right B. Drag A somewhere near the center of the sketch. Double-click on A.

What happens?

___________________________________________________

Draw a segment above the line with A as one of the endpoints. Rename the other endpoint of the segment C. Measure the length of the segment. Make sure the measurement is visible on the screen.

Measure <BAC. Drag point C until <BAC equals approximately 30 degrees. Highlight the segment and point C. Choose "Rotate..." from the TRANSFORM menu. Type in 90 and click OK.

How does the computer label the new point?

___________________________________________________

Change the label of the new point to D. Have the computer draw a segment connecting points D and C.

Describe how you did this:

___________________________________________________

___________________________________________________

Change the color of the segment you just had the computer draw to green. Double-click on the new segment.

What happens?

___________________________________________________

Highlight segments AD and AC and point A. Choose "Reflect" from the TRANSFORM menu.

What happens?

___________________________________________________

What label did the computer give the new point?
___________________________________________________

Change the label of the new point to E. Measure the following angles and make sure the measurements are visible on the screen:
<DEC, <EDC, <ECD, <ECA, <EDA, and <DAC.
Measure the distance from points D and C. Measure the length of segment DC.

What is DC?

___________________________________________________

Highlight points D, E, and C in that order. Choose "Polygon Interior" from the CONSTRUCT menu. Change the "Shade" of the polygon interior to 25%. Re-highlight points D, E, and C in that order. Choose "Arc Through 3 Points" from the CONSTRUCT menu.

What happens?

___________________________________________________

Highlight points D, A, and C in that order. Choose "Arc Through 3 Points" from the CONSTRUCT menu. Put your name somewhere on the screen. Print the sketch by choosing "Print Preview..." from the FILE menu. Be sure to click on the button for "Scale To Fit Page" before clicking on the "Print..." button.