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From Karnataka Open Educational Resources
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, 16:47, 26 December 2013
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# The teacher can reiterate a triangle and its elements.
# The teacher can reiterate a triangle and its elements.
# Show them the geogebra file and explain the thales theorm or the basic proportionality theorm which states that a line segment drawn parallel to one side of a triangle divides the other two sides proportionally.
# Show them the geogebra file and explain the thales theorm or the basic proportionality theorm which states that a line segment drawn parallel to one side of a triangle divides the other two sides proportionally.
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# She can prove the theorm for different measurements by moving the vertices of the triangle and also by moving D, to change the position of parallel line.
# Also she can use the same file to explain the converse theorm which states that a line segment that divides any two sides of a triangle proportionally is parallel to the third side.
# Also she can use the same file to explain the converse theorm which states that a line segment that divides any two sides of a triangle proportionally is parallel to the third side.
# While proving converse theorm, she can show that since the corresponding angles <ADE = <ABC and <AED = <ACB, the line DE that divides AB and AC proportionally is infact parallel to BC.
# While proving converse theorm, she can show that since the corresponding angles <ADE = <ABC and <AED = <ACB, the line DE that divides AB and AC proportionally is infact parallel to BC.