THE TRIANGLE AND ITS PROPERTIES 123
A triangle in which two sides are of equal lengths is called an isosceles triangle.
Fig 6.20
From a piece of paper cut out an isosceles triangle XYZ, with XY XZ (Fig 6.20).
Fold it such that Z lies on Y. The line XM through X is now the axis of symmetry (which
you will read in Chapter 14). You find that ∠Y and ∠Z fit on each other exactly. XY and
XZ are called equal sides; YZ is called the base; ∠Y and ∠Z are called base angles and
these are also equal.
Thus, in an isosceles triangle:
(i) two sides have same length.
(ii) base angles opposite to the equal sides are equal.
- Find angle x in each figure:
TRY THESE