http://libraries.mit.edu/archives/exhibits/exam/geometry.htm...
http://libraries.mit.edu/archives/exhibits/exam/geometry.htm...
1. Construct a triangle ABC. Construct a line parellel to AB through C. Alternate angles and angle sum of triangle shows it is 180 degrees
2. Use congruent triangles
3. A number of ways doing this. I would cut it into two triangles
4. 360/6 = 60 degrees. Thus each sector is a equilateral triangle.
5. 100 pi
6. Basic algebra, let x be the length of the perpendicular. x = 12, solve for sides using Pythagoras. 20 and 15
7. x : x^2
Would expect to be year 7 or year 8 level.
If I remember correctly, my school district didn't offer true algebra until 8th grade, for honors students only, in a class that started an hour before any regular class. Hardly elementary.
At least, my year was given two years of algebra.