Conclusion:Triangle ABC is a right triangle,5. A right triangle maybe constructed by makingthe sides 3", 4", and 5" or multiples or fractionsthereof.Problem:Construct a right triangle with sides of 1 1/2", 2", and 21/2" (1/2 of 3,4, and 5).Solution:Step 1. Draw line AB = 2".Step 2. From A, draw an arc equal to 1 1/2".Step 3. From B, draw an arc equal to 2 1/2".Conclusion:Triangle ABC is a right triangle,QUADRILATERALSA quadrilateral is a four-sided plane shape. Thereare many types, but only the trapezoid, parallelogram,rectangle, and square are described here.1. A TRAPEZOID is a quadrilateral having onlytwo sides parallel. If the other two sides areequal, it is an isosceles trapezoid. BF is thealtitude of the trapezoid.2.3.A PARALLELOGRAM is a quadrilateral hav-ing opposite sides parallel.a.b.c.d.e.f.AB is parallel to CD.AC is parallel to BD.AD and CB are diagonals.Diagonals bisect each other so CO = OB andAO = OD.Opposite angles are equal ACD = DBA andCAB = BDC.If two sides of a quadrilateral are equal andparallel, the figure is a parallelogram.A parallelogram may be constructed if twoadjoining sides and one angle are known.A RECTANGLE is a parallelogram having oneright angle.a. ABCD is a parallelogram having one rightangle. This, of course, makes all angles rightangles.b. AC and BD are diagonals.c. O is the midpoint of AC and BD andOB = OC = OD = OA.d. O is equidistant from BC and AD and is alsoequidistant from AB and CD.e. A rectangle may be constructed if twoadjoining sides are known.AII-11