View Tube Triangulation

Pete Insley Jones Metropolitan H. S.
606 S. State St.
Chicago IL 60605


Measuring Distance; Estimating; Averaging; Standard deviation

Materials Needed:

Meter sticks, rulers, cut down paper towel cardboard tubes


First, get the students to estimate the height of the chalkboard or the
doorway. List the estimates and use a calculator to find the average and
standard deviation.

Stand far enough away so that you can see the entire object in the tube.
Use a proportion to find the height of the object.

Height of object = Distance of tube Distance to object Length of tube List the calculations and again find the average and the standard deviation. Take some time to discuss what they mean again. Now get a couple of students to measure exactly how big the object is. Have a prize for the best estimate of measurement. Performance Assessment:

Collect paper with original estimate and calculation of height. Have
students write a short paragraph stating how well they think they did on the


You can find percentage error in this lab and it has some new meanings to
the students. Have them find their % of error. You can also find the probable
percentage of error from the standard deviation.

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