Geoboard picture

Click the check box "show picture". By moving the yellow point you can change the size of the square.
Tim is a painter. He has to paint a picture of an 8 dm high bear (with santa claus hat) on a window. For testing, he already painted a 2 dm high picture; he needed 5 ml of color for it. How much color will Tim need for the big bear?

Information: Geoboard picture