How do we calculate the area of rectangles and triangles ?

Aim: How do we calculate the area of rectangles and triangles ?

Triangle Area Conjecture= (1/2)bh
The Area of a triangle is given by the formula A=(1/2)bh. A is the Area, B is the length of the base, and H is the height of the triangle.

Example:

 The Triangle ABC.
The Length of AC is 9mm and the length of AB is 20mm.

Step1: Know the given information, The problem gave you already that the length of the base is 9mm and also that the height is 20mm.

Step2: plug the new information in the formula A=(1/2)bh 
Ex: A=(1/2) 9 X 20

Step 3: Multiply The base and the height
Ex: 9 X 20= 180

Step4: Once you got your answer divide the answer by 2
180/2= 90

And the answer to the problem above is 90mm^2