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The "Many Triangles" problem

In the figure below, the lines BC, AD and FT are parallel. Lines BF, GH and CT are parallel. Press the browser 'refresh' button to clear answers.


Problem 1
How many right triangles are there? show answer
Between 16 and 22
( Note: if you are assuming the angle abk, and the three others like it, is 90° you will need to prove it first).
Problem 2
How many isosceles triangles are there? show answer
More than 12
Problem 3
How many triangles altogether? show answer
More than 30
Problem 4
What is the total area of the figure? show answer
Between 645 and 723 square units

Resources (and perhaps clues)
triangle, right triangle, isosceles triangle, area of a triangle
(C) 2007 Copyright John Page