Year 10 Interactive Maths - Second Edition

Basic Geometry

Geometry is used in surveying, navigation, astronomy and many practical occupations. Astronomers use geometry to measure the distance from the Earth to other planets, and chemists use it to comprehend the structure of molecules. Geometrical drawings are widely used by surveyors, architects and engineers. Navigation by sea and by air depends on accurate geometry.

In this chapter we will revise the angle facts of geometry, the main features of triangles and quadrilaterals; and their use in solving numerical problems.

Angle Facts of Geometry

You should be familiar with the following angle facts of geometry:

Example 1

Find the value of the pronumeral(s) in each of the following diagrams:

Solution:

Key Terms

geometry, angle facts of geometry, complementary angles, supplementary angles, adjacent angles forming a straight line, angles at a point, parallel lines, transversal, alternate angles, corresponding angles, vertically opposite angles, allied angles, co-interior angles