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diff --git a/Save_Mathematics/P4/map412m10/map412m10a07/source.txt b/Save_Mathematics/P4/map412m10/map412m10a07/source.txt deleted file mode 100755 index 656cb3a..0000000 --- a/Save_Mathematics/P4/map412m10/map412m10a07/source.txt +++ /dev/null @@ -1,22 +0,0 @@ -<h1>Introduction: Geometric Figures, the Parallelogram</h1> - -The computer will show a drawing of a square. It will introduce the properties of a square: all sides are equal, all interior angles are right angles, the diagonals bisect the interior angles, the diagonals intersect to form right angles. Opposite sides are parallel. - -The computer will ask whether it is possible to have a square with all sides equal in length but not parallel? I - -If we have a figure with four equal sides and one of the interior angles is a right angle, is it a square? - -When we draw a diagonal, we form two triangles (right triangles). What do we know about the other interior angles of a right triangle? Can you see why we know the diagonal bisects (divides in half) the interior angles of the square? - -Think about the base of the square. The two diagonals from the bottom corners of the square intersect to form a triangle. From what we know about the bottom two angles, can we tell what kind of triangle it is. (Hint: if a triangle has two 45 degree angles, what is measure of the third angle). From this, can we say the the angle formed by the intersection of the diagonals is a right angle (90 degree) angle. - -If the bottom side of the square forms right angles with the right and left sides, we know the right and left sides are perpendicular to the bottom side. -We also remember that two different perpendicular lines are parallel to each other. - -How can we draw a square? Perhaps we draw the base side. It's length will be the length of the other sides. Now we need to draw two lines perpendicular to the base (use a square, for example, a corner of a copy book). Then we could use a compass to measure the length of the base and mark the length of the perpendicular sides. If we connect the perpendicular lines at the point measured by the compass, we have a square. - -The computer will illustrate these points using an animated diagram of a square. - -The computer will introduce the concept of the perimeter as the sum of the lengths of the sides. It will point out that for a square the perimeter is 4x the length of one side. - -The computer will remind the student that the surface area of a square is the square of the length of a side. |