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?
(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?
Problem 3
How many triangles altogether?
Problem 4
What is the total area of the figure?
 Full answer list

Resources (and perhaps clues)