Scale (Skala)

Ämne / Topic

Using scale to find area and lengths.

Inlärningsmål / Learning Goals

Understand the meaning of scale. Be able to use scale to determine the image or real size.

Google Slides & Videos

Lektionssteg / Steps in the lesson:

1. Lektionsuppvärmning / Lesson warm up / Hook / Review from previous lesson

What is scale?

Scale is a concept that is used in arranging, measuring or quantifying events, objects or phenomenon in any sequence.

Ratio of the size of an object as drawn to its actual size.

Size of picture: Size in reality.

Length scale = length of image

length in reality

If the scale is larger than 1, the picture is an enlargement.

If the scale is less than 1, the image is a reduction.

2. Introduktion till lektionen / Introduction to the lesson content

The main part of the lesson, will start with the learners watching a video on scale (see attached).

While the video is playing, the teacher will stop it at various points and ask learners questions on what was said, to gauge their understanding and keep them active in the lesson.

3. Aktiviteter / Key Activities

4. Kolla vad eleverna kan / Check for understanding / Exit ticket

An artist drew a picture of a lady bug. the picture of the lady bug was 15 cm. The scale of the lady bug drawing to its size in reality is 3:1.

What is the actual size of the lady bug.

Length scale = Length of the image

Length in reality

Length scale: 15 cm = 3

x cm 1

Length scale: 3x cm = 15 cm

Length scale: 3x cm = 15 cm

3 3

Length scale : x = 5 cm

so the lady bug in reality is 5 cm.

Question 1:

Shapes P and Q are mathematically similar. The area of shape P is 6cm²

a) Calculate the size of missing side-length x.

b) Calculate the area of shape Q.

5. Stängning / Closure / Summary of lesson

When do we see scale used in the real world? Why are scaled drawings useful?