WASHINGTON STATE MATHEMATICS COUNCIL
1999 MIDDLE SCHOOL MATH OLYMPIAD
SEVENTH GRADE GEOMETRIC SENSE
Make sure you include proper units in your answer!

7

1. The figure ABCDEF at right is made up of two congruent trapezoids, ABCF and DEFC, where trapezoid ABCF has been rotated to create trapezoid DEFC. Find the area of the figure ABCDEF.

 

2. How many equilateral triangles of any size can be made using the "pegs" on the triangular geoboard at right? Count triangles in different positions on the board as different triangles. All of the pegs are equally spaced.

 

 

 

 

3. On the answer sheet, draw the figure that would result when the figure at right has been rotated about point R through an angle of 180 degrees.

 

 

4. Triangles A and B are similar triangles. (Their shapes are identical in proportion but triangle A is smaller than triangle B.) Write a sentence stating how the perimeter of triangle A compares in measure with the perimeter of triangle B.

 

 

 

 

5. To the nearest percent, what percent of the area of the square is the area of the circle in the figure at right?