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Constructing 2D Shapes. Grade 6 Geometry Unit. Re-cap. Given two of the three angles in a triangle, how could we find the third angle? Given SAS how could we construct a triangle? Do you think we could construct a triangle give side side side (SSS)?
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Constructing 2D Shapes Grade 6 Geometry Unit
Re-cap • Given two of the three angles in a triangle, how could we find the third angle? • Given SAS how could we construct a triangle? • Do you think we could construct a triangle give side sideside (SSS)? • Do you think we could construct a triangle given angle side angle (ASA)?
Constructing Triangles with SSS • Goal: to construct triangle ABC with sides AB=6cm, AC=5cm, and BC is equal to 4cm • Step 1: Draw line AB which is 6cm long A B • Step 2: Set the compass so the pencil and the compass point are 5cm apart • Step 3: Place the Compass on point Aand draw an arc 6cm 5cm
Constructing Triangles with SSS • Step 4: Now, set the compass and pencil so that they are 4cm apart. • Step 5: Place the compass point on B and draw an arc so the lines insert. The point where the arcs insert, label it C • Step 6: Draw segments AC and BC to complete the triangle, and label each segments with its length
Constructing Triangles with AAA • Goal: Draw a triangle that has the following degrees: <A 100 degrees, < B45 degrees and <C 35 degrees • Step 1: Draw a tentative baseline (this means you will probably erase some of the line after all your angles are drawn) • Step 2:Label the first point with A A • Step 3: At point A, measure 100 degrees with your protractor, make a dot at 100 degrees and mark your dot with B B • Step 4: Connect points A and point B A
Constructing Triangles with AAA • Step 5: From point B, measure 45 degrees with your protractor, and mark that point with a dot and label it C, connect B and C • Connect point A and C to form your triangle
Constructing a Parallelogram • Goal: To construct a parallelogram BACD where AD=BC=5cm, BA=DC=2cm, Angle ABC=120 degrees, and angle BDC=60 degrees • Step 1: Use a ruler to draw a line segment that is 5cm long B 5cm C HINT: Since BC is 5cm, what’s AC? • Step 2: At point B, measure and mark 120 degrees. Draw segment BA 2cm long in the direction of 120 degrees. 2cm 120 degrees 5cm
Constructing a Parallelogram • Step 3: Use a protractor to measure 60 degrees at point C, and draw a line segment that is 2cm long A C 120 degrees 60 degrees B D Step 4: Draw line segment AD to complete the parallelogram 5cmA C 2cm 2cm B D
Task... • A triangle where... • PQ=6cm, QR=8cm, PR=10cm • All sides of CDE are 65mm • HFG=50 degrees, =60 degrees, =70 degree • A quadrilateral where... - <C=110 degrees, <D=130 degrees, <F=50 degrees