12.5 Making figures with a tangram.

Use all the pieces of tangarm to form a trapezium, a parallelogram, a rectangle and a square.

Also make as many different kinds of figures as you can by using all the pieces. Two examples have been given for you.



Example 10 :

In trapezium ABCD, AB is parallel to CD. If ∠ A = 50°, ∠B = 70°. Find ∠C and ∠D. Solution : Since AB is parallel to CD ∠A + ∠D = 180° (interior angles on the same side of the transversal) So ∠D = 180° – 50° = 130°

Similarly, ∠B + ∠C = 180° So ∠C =180° – 70° = 110°



Example 11 : The measures of two adjacent angles of a parallelogram are in the ratio 3 : 2. Find the angles of the parallelogram.<

Solution : The adjacent angles of a parallelogram are supplementary.