Areas of irregular object

Previous knowledge
Formula of a square, a=x2

using a caliper

Activity
Determine the area of your hand outline

Activity 2nd
Consider a better approach, by includying half squares and sum them up

activity 3rd
Revise your constants by using a vernier
 * by measuring only a square (See figure 1)

by using a good rule
 * Measure exactly 10 squares

(see down)