Warm-Up 1
Day 9: Geometry and Scale Drawings
Review measurement, area, angle reasoning, and simple scale drawings.
Student Goal
I can use measurement and scale to solve geometry problems.
Why It Matters
Geometry and scale help students reason about maps, models, layouts, design, and measurement in 7th grade math.
Warm-Up
Warm-Up 2
If a circle has radius 4, what is its diameter?
Warm-Up 3
A scale says 1 inch represents 5 feet. What does 2 inches represent?
Short Lesson
Standard Focus
NC.7.G: Geometry
Student-Friendly Standard Goal
I can use formulas, measurement, and scale relationships to solve geometry problems.
- Geometry problems often start with identifying the figure and the measurements you know.
- Scale drawings use a smaller or larger model to represent a real object.
- A scale factor tells how measurements change from the drawing to the real object.
Guided Examples
Guided Example 1
Use a Scale Drawing
On a map, 1 inch represents 6 miles. A trail is 4 inches long on the map. How long is the real trail?
Step 1
1 inch = 6 miles
What does 4 inches mean?
Guided Example 2
Find Area
A triangular garden has base 10 feet and height 6 feet. What is its area?
Step 1
A = 1/2bh
Which measurements go into the formula?
Practice
Problem 1
Find the perimeter of a rectangle with sides 8 and 3.
Problem 2
Which is the correct formula for area of a triangle?
Problem 3
A scale drawing uses 1 cm = 3 meters. What is the real length for 5 cm?
Problem 4
True or false: The diameter of a circle is twice the radius.
Problem 5
A student finds rectangle area by adding length plus width. What should they do instead?
Reflection
How are you feeling about today's skill?
Optional reflection: How does scale help us represent real objects?