standard_description: Understand that a two-dimensional figure is congruent to another if the second can be obtained from the first by a sequence of rotations, reflections, and translations; given two congruent figures, describe a sequence that exhibits the congruence between them.
problem_activity: Task
Hand span is a measure of distance from the tip of the thumb to the tip of the little finger with the hand fully extended.
Each student places his or her dominant hand on the edge of a piece of paper with the hand fully extended.
The student should make a mark at the tip of the thumb and the tip of the little finger. The distance between marks is the length of the hand span.
The student should measure his or her hand span with a centimeter ruler and round the measurement to the nearest whole centimeter.
Each student should record his or her measurement on a piece of paper.
The teacher can ask each student for his or her measurement and record the data using a line plot with a horizontal scale marked off in whole centimeters. Alternatively, the teacher can set up the line plot and ask each student to come record his or her own hand span, showing the students how by recording the teacher's hand span.
Students should comment about patterns they observe the line plot and write or discuss the answers to these two questions:
What are the largest and smallest spans?  What is the difference between the largest and smallest spans?
Use words to describe the shape of the data set.  Does it appear taller in the center like a mountain?  Are there peaks in more than one place?  Is the shape of the data flat like a table top?  Are there gaps?  Are some hand spans much bigger or smaller than the others?


aligns: no