TRADE OF PLASTERING - eCollege

Module 1 – Unit 4 Rendering Walls
4.0 Interpret and Draw Quadrilaterals
Key Learning Point
Construction of basic quadrilaterals
4.1 Basic Quadrilaterals
Quadrilaterals
A quadrilateral is a figure bounded by four straight lines, as in Figure 2 below.
Figure 2 Figure 3
It can be split into two triangles with a diagonal line, as in Figure 3.
The sum of the angles in a triangle is 180 °, therefore the sum of the four
angles in a quadrilateral must be 360 °. If three of the angles are known, the
fourth can be found.
Example:
In the quadrilateral shown in Figure 4 find the size of the angle x.
Figure 4
We know the sum of the angles ABCD is 360 °, therefore
X = 360 ° - (82 ° + 78 ° + 75 °)
= 360 ° - 235°
= 125°
Plastering Phase 2 16 Revision 1.0 July 2008