Math CAMBRIDGE-BOOK(8.4 and 8.3) for year8

Welcome to Mr.Zul’s Class-Altaqwa College Indonesia

By: Ujay(as a leader),Zikri,Nicky,Ihsan

In this BLOG we(Shiddiq)will explain and tell to do the exercise(cambridgebookmath)8.4 and 8.3, Thats about Drawing nets of solids(8.4) and Classifying Quadrilaterals(4.3)--->LETS SEE:)

[8.3]A quadrilaterals is 2D shape with four straight sides.

A DIAGONAL is a line that join two opposite corners of a quadrilaterals.

Every quadrilaterals has two diagonals BISECT each other.The words 'bisect'

means to cut in half

In a rectangle the diagonals bisect each other.

In a kite only one diagonal bisect the other

In some quadrilaterals the diagonals cut or bisect each other at 90 degrees(second picture)

In a square the diagonals bisect each other at (first picture)

In a paralellelogram the diagonals bisect each other,but not at (second picture)

Here is a summary of the properties of the special quadrilaterals that you should know.

                                                                  

[8.4] Drawing nets of solids
A net shows the 2D layout of a 3D shape.
The net will fold up to make the solid.

To work out the net of a 3D object, imagine cutting it along its edges and unfolding it.
You need to be able to make a sketch of the net of a 3D solid. You also need to be able to make an accurate drawing of the net of 3D solid. In an accurate drawing all the lengths must be exactly the correct measurements.
There are often different ways to draw the net of 3D solid. For example, here are three ways you could draw a net of a cube:


Here's is an example of question from a test:

Draw a sketch of a net of a tetrahedron.Answer:  
Why does it look like a net for a triangular based pyramid?
Well that's what is, tetrahedron is the same thing as a triangular based pyramid.