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 TOPICS This page:   triangles/polygons    Search   Dr. Math See also the Dr. Math FAQ:   geometric formulas and   naming polygons   and polyhedra and   Pythagorean theorem Internet Library:   triangles/polygons MIDDLE SCHOOL About Math Algebra    equations    factoring expressions    graphing equations Arithmetic    division    exponents    factorials    factoring numbers    fractions/percents    logarithms Definitions Geometry    2-dimensional      conic sections/        circles      triangles/polygons    3D and higher      polyhedra History/Biography Logic Measurement    calendars/      dates/time    temperature    terms/units Number Sense    factoring numbers    negative numbers    pi    prime numbers    square roots Probability Puzzles Ratio/Proportion Statistics Word Problems Browse Middle School Triangles and Other Polygons Stars indicate particularly interesting answers or good places to begin browsing. Selected answers to common questions:     Classifying quadrilaterals.     Polygon diagonals.     Pythagorean theorem proofs. Thinking about the Maximum Area Enclosed by a Fence [04/15/2004] You have 2000 meters of fencing. What is the largest area you can enclose with it using various shapes? Three Facts Necessary to Find a Triangle [09/13/2002] Is there a formula for solving for a right triangle given only the length of one leg and no angles except for the known 90-degree angle? Tiling a Floor [06/30/1999] How many square yards is a 12ft. by 15ft. room? How many 8" x 8" tiles would you need for a 30 sq. ft. room? Total Area of Multiple Objects [07/18/2002] I have 6 windows and want to know the total square feet. Do I compute the areas separately, or add the dimensions and use those to compute the area all at once? Triangle and Trapezium Ratio [10/26/1998] ABCD is a square with sides of length 4 cm. Find M on BC so that the ratio of triangle ABM and trapezium ADCM is equal to 1/3. Triangle Area [08/13/1997] How do you find the area of a triangle? Triangle Geometry: Sides and Edges [6/2/1996] If the angles of a triangle are equal, does it necessarily mean that the sides are also equal? Triangle Inequality Theorem [03/09/2001] The lengths of the sides of a non-isosceles triangle, in size order, are 5, x, and 15. What are all possible integral values of x? Triangles: Angle Sums [05/15/2002] Can you draw a triangle in which the sum of any two angles - no matter which two you pick - is always less than 120 degrees? Triangles: Height and Angle [4/12/1996] A tree casts a shadow 30 ft and makes an angle of 47 degrees with the ground. How high is the tree? Triangles with Specific Lengths and Angles [3/24/1996] My base is 32 inches and my angle can not exceed 35 degrees. How long will my sides be and what is the inside angle? A Triangle with Three Right Angles [12/01/1999] How can you make a triangle with three right angles? Two Column Proof of a Theorem [08/12/1998] Write a two-column proof and give numbered statements with reasons.... Two-Sided Polygon? [12/01/2003] My 5th grade math teacher said that we had to draw a polygon using two straight lines. Is this possible? Types of Triangles [02/24/2003] What is the the difference between equilateral, isosceles, and scalene triangles? How can I remember which name goes with which triangle? Understanding Rectangle Area and Perimeter [11/08/2002] True or false: if the perimeter of a rectangle increases, the rectangle's area always also increases. Units Crossed by a Line Segment [2/2/1996] If you connect (0,0) to (p,q) where p and q are positive whole numbers, how many squares do you go through? Using a Parallelogram to find the Area of a Triangle [06/26/2001] What is the area of a triangle with a height of 12 inches and a base of 3 inches? Using a Protractor [06/28/1998] How do you construct two parallel lines and intersect them making a 65-degree angle? Venn Diagram to Classify Quadrilaterals [01/02/2003] I am looking for a Venn diagram that will accurately display the relation among trapezoids, parallelograms, kites, rhombi, rectangles, and squares. What Does a Myriagon Look Like? [10/30/2002] I am looking for a picture of a myriagon. What is an N-gon? [06/01/1998] Can you explain the statement: "In an N-gon, n-3 diagonals can be drawn from one vertex"? What is a Vertex? [12/06/2001] And what does vertices mean? What is Circumference? [06/25/2001] My friend told me it's somewhat like the measurement of the outside of a circle, but I don't understand that. What is Length in a Rectangle? [05/31/1999] Is the length of a rectangle the longest side, whether vertical or horizontal? Why are Manhole Covers Round? [05/09/2000] Why are most manhole covers round? Why aren't manhole covers on the streets squares or rectangles? Why Do the Angles of a Triangle Add to 180 Degrees? [4/17/1996] We were wondering why all the angles in a triangle add up to 180 degrees. Why do the Midpoints of Quadrilaterals Make a Parallelogram? [2/7/1996] Why is it that if you join the midpoints of any quadrilateral you always get a parallelogram? Why So Many Shapes? [05/07/2001] I just want to know why there are so many shapes in the world. World War II Window Blackout [10/21/2001] Mr. Brown had a square window 120cm x 120cm, but the only material he could find was a sheet of plywood 160cm x 90cm; same area, different shape. He drew some lines and cut out just two congruent shapes, which he joined to make a square of the correct size. How did he do it? You Can't Trisect an Angle [7/16/1996] Who proved you can't trisect an angle? Page: [

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