Using a Protractor

Wala: Measuring angles accurately.

L.O: Measuring angles using a protractor.

Multiplication table.

Table 9

Relevance of angles in life.

In the construction industry, angles make the difference of whether a building is safe or not. Architects and contractors need to calculate angles very precisely to create a structure which stands upright and allows rainwater to run off the roof. Furthermore, without ensuring all structures are built with straight lines, construction workers cannot guarantee that windows and doors will fit. If these angles and lines are calculated incorrectly, or they are not built accurately, the structure could collapse.

Using protractor.

Protractors usually have two sets of numbers going in opposite directions.

Be careful which one you use!

Measuring.

Let students practice measing angles using technology before trying it in their note books. Use the link below.

https://www.mathsisfun.com/geometry/protractor-using.html

Using protractor.

-Place the midpoint of the protractor on the VERTEX of the angle.

-Line up one side of the angle with the zero line of the protractor (where you see the number 0). 

-Read the degrees where the other side crosses the number scale.

Pair work.

NIM page 72 No 1 a-e

Measure the angles accurately.

Measuring angles.

What are the steps to follow when measuring angles using a protractor?