yngirl2014
New member
- Joined
- Jan 13, 2012
- Messages
- 1
Materials
• Four drinking straws (pre-cut to different lengths)
• One pipe cleaner (3-inch piece)
• Ruler
Complete the table below with the data from Activities 1 and 2.
Activity 1
1. Choose two straws and measure the length of each straw. Be sure to include units.
Each straw represents the side of a triangle.
2. Put the pipe cleaner halfway into the end of one straw. Then, put the other straw on
the other half of the pipe cleaner so that the straws are just touching. Bend the pipe
cleaner to make an angle.
3. Open and close the angle along the ruler to determine two possible lengths for a third
straw that could be the third side of a triangle.
4. Open and close the angle along the ruler to determine two lengths for a third straw that
would not work for the third side of a triangle.
5. Let the length of the third side of the triangle be x. Write an inequality to show the
longest and shortest possible lengths for the third side.
Activity 2
Now use the other two straws (the ones that have not been used) and repeat the steps in Activity 1.
Activity 3
Choose any three of the four straws and create a triangle. Which angle in the triangle would be the
largest? Which would be the smallest? Explain.
Summary
Determine the possible lengths for the third side of a triangle whose first two sides
measure a and b.
• Four drinking straws (pre-cut to different lengths)
• One pipe cleaner (3-inch piece)
• Ruler
Complete the table below with the data from Activities 1 and 2.
Activity 1
1. Choose two straws and measure the length of each straw. Be sure to include units.
Each straw represents the side of a triangle.
2. Put the pipe cleaner halfway into the end of one straw. Then, put the other straw on
the other half of the pipe cleaner so that the straws are just touching. Bend the pipe
cleaner to make an angle.
3. Open and close the angle along the ruler to determine two possible lengths for a third
straw that could be the third side of a triangle.
4. Open and close the angle along the ruler to determine two lengths for a third straw that
would not work for the third side of a triangle.
5. Let the length of the third side of the triangle be x. Write an inequality to show the
longest and shortest possible lengths for the third side.
Activity 2
Now use the other two straws (the ones that have not been used) and repeat the steps in Activity 1.
Activity 3
Choose any three of the four straws and create a triangle. Which angle in the triangle would be the
largest? Which would be the smallest? Explain.
Summary
Determine the possible lengths for the third side of a triangle whose first two sides
measure a and b.