Distance Formula to Find Area and Perimeter

Area & Perimeter in Coordinate geometry

by Teacher Afiqah

​9 Science 1

​SM Katok

Poll

​LO: Solve problems about perimeter and area given the coordinates

• I understand

• I don't understand

Poll

Steps to success:

1. ​On a graph, plot the coordinates accurately.

2. Join the points using a straight line to form a shape.

3. Write the distance formula

4. Subsititute & calculate the distance between the 2 points.

5. Calculate perimeter & area of basic shapes

• I get it

• I don't get it.

Multiple Choice

• BLUE

• GREEN

• YELLOW

• RED

Multiple Choice

Calculate the distance of AB.

Correct your answers to 1 decimal place.

$$d=\sqrt[]{(𝑥_2−𝑥_1)^2+(𝑦_2−𝑦_1)^2}$$  

• 7.2 units

• 7.1 units

• 7.0 units

Multiple Choice

• BLUE

• GREEN

• YELLOW

• RED

Multiple Select

What do you need to calculate the area of a triangle?

You may choose more than 1 answer.

• perpendicular height

• height

• base

• diagonal length

Multiple Choice

What is formula for the area of trapezium?

• $$\frac{1}{2}\times\left(a\times b\right)\times perpendicular\ height$$  

• $$\frac{1}{2}\times\left(a+b\right)\times height$$  

• $$\frac{1}{2}\times\left(a\times b\right)\times height$$  

• $$\frac{1}{2}\times\left(a+b\right)\times perpendicular\ height$$  

Fill in the Blanks

The area of the trapezium is

squared metre.

Read the instructions carefully

1. ​Prepare ruler, pencil, calculator.

2. ​Get ready with your graph paper.

3. ​If you don't have graph paper, then a lined paper is fine.

Open Ended

​Using 1 cm = 1 unit

Draw x-axis with range -3 to 6

Draw y-axis with range -1 to 5

​Plot the vertices of A(-2,0), B(5,0) and C(1,4)

​Join the points using straight lines.

​

Describe the shape you drew?

Fill in the Blanks

​Based on your diagram, calculate the length of AB.

$d=\sqrt[]{(𝑥_2−𝑥_1)^2+(𝑦_2−𝑦_1)^2}$

include the units in your answer 

Fill in the Blanks

​Based on your diagram, calculate the length of AC. $d=\sqrt[]{(𝑥_2−𝑥_1)^2+(𝑦_2−𝑦_1)^2}$

include the units in your answer 

Fill in the Blanks

​Based on your diagram, calculate the length of BC. $d=\sqrt[]{(𝑥_2−𝑥_1)^2+(𝑦_2−𝑦_1)^2}$

include the units in your answer.

Correct your answer to 2 decimal place

Fill in the Blanks

​Based on your diagram and calculated lengths, calculate the perimeter of ABC.

Correct your answer to 2 decimal place and include units.

Multiple Choice

The area of triangle ABC ______ squared units

• 14

• 15

• 14.5

• 15.5