Sum of the angles of a triangle
1.
Name: ______________________
Carefully draw triangles with the specifications below. Use a protactor to measure the angles and calculate
the sum of the angles. Record your results in the table below.
Angle
Angle
Angle
Sum
Acute
Right
Obtuse
General
Based on this data, can we conclude that the sum of the angles of every triangle is some constant? Explain.
2.
Originally, the sum of the angles of a triangle was taken to be a line. Explain.
3.
Use the triangles provided to give a tangible demonstration of the original statement of the angle sum of a
triangle.
Explain your work here. Tape the pieces onto the back.
4.
Explain why none of the above, including the statistical analysis, is a proof.
Try to prove that the sum of the angles of any triangle is 180°.