Similar figures and the two conditions for similar triangles. Then Thales' theorem, its converse, and the way a line parallel to one side cuts the other two in the same ratio.
3 lessons, about 1 h 15 min3 simulations10 problems3 practice questionsPython in every lesson
Created by StemPy LabTwo figures are similar when their matching angles are equal and their matching sides are in the same ratio. That ratio is the scale factor. A method for finding unknown sides of similar triangles, with a simulation, practice and a program.
A line drawn parallel to one side of a triangle cuts the other two sides in the same ratio. We prove this with areas, then use it to find unknown lengths, with a simulation, practice and a program.
If a line cuts two sides of a triangle in the same ratio, it is parallel to the third side. We prove this converse, use it to show lines are parallel, and meet the midpoint theorem and the diagonals of a trapezium.
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