Presentation on theme: "Estimate the angle?Now measure the angle? 150º. Estimate the angle?Now measure the angle? 215º"— Presentation transcript:
Estimate the angle?Now measure the angle? 150º
Estimate the angle?Now measure the angle? 215º
Constructing triangles Aim: To construct triangles using a protractor. 60º
Draw a triangle with one side 6cm and angles at each end of 30º and 70º. 6 cm Mark 30º Mark 70º
Draw a triangle with a side 12 cm and side 9 cm with an angle of 75º between them. Mark 75º 12 cm
Three ways to construct triangles. When constructing triangle we need a combination of angles of lengths. We can construct triangles with a compass if we have the lengths of the 3 sides (S S S). We can construct triangle using a protractor if we have the length of 1 side and the measurement of 2 angles ( A S A ). We can construct triangle using a protractor if we have the length of 2 sides and the measurement of 1 angles ( S A S ). Note:To construct triangles, we need to know the length of at least 1 side plus 2 other pieces of information.
S S S Triangles 5cm7cm9cm 6cm6 cm4cm 10cm8cm7cm 6cm8cm10cm 7cm7 cm7 cm Task and Homework Construct the following triangle: A S A Triangles 40º7cm 50º 45º 6 cm 45º 20º 8cm 100º 60º 8cm 60º 110º 7 cm 45º A S A Triangles 7cm50º4 cm 6 cm45º6 cm 8cm100º6 cm 8cm60º8 cm 7 cm 45º 6 cm