Question number 12. The rectangle ABCD in the picture consists of four equal rectangles. If BC has length of one centimeter, what is the length of side AB? Here is our diagram. I will make a copy of it and enlarge it so we can better see what is going on in this problem. So let me scale this up to about twice the size, and then let's make sure all the information in the problem is accounted for. We have a side BC of length equal to one centimeter. Let me emphasize that here in the diagram in red. Of course, since these are rectangles, the parallel side must also have a length of one centimeter. And now we notice that we have just drawn a red line along two of the shorter edges in these equal rectangles. So here is, in blue, one of the shorter edges right on top of the red, and here is another one. And together these make up the longer side here. And that allows us to say that the dimensions of these four identical rectangles are one half centimeter by one centimeter. And to calculate the length of side AB, we have here a piece that measures one half of a centimeter, a piece that measures one centimeter as given in the problem, and then another piece of length of one half of a centimeter. So together we add these up, and we have the length of side AB equal to two centimeters. So the answer to number 12 is going to be C. Two centimeters is the length of AB.

rectangle

geometry

AB length

smaller rectangles

solution