Lesson 2-2: Unit Conversions & Proportions

Scenario: International Travel - Learn to convert between measurement systems for global travel!

Duration: 60-75 minutesScenario: International Travel

Learning Objectives

Convert between metric and imperial measurement systems
Use proportions to solve unit conversion problems
Apply conversions to real-world travel scenarios
Understand conversion factors and their applications

Weight Conversion Scenario

The Problem

You're traveling from the US to Europe. Your luggage weighs 120 pounds. What is this weight in kilograms? (1 pound ≈ 0.454 kg)

Solution using proportion:

1 lb / 0.454 kg = 120 lb / x kg
Cross multiply: 1 × x = 0.454 × 120
x = 54.48 kg

Conversion Methods

Method 1: Direct Multiplication

120 lb × 0.454 kg/lb = 54.48 kg

Method 2: Proportion

1 lb : 0.454 kg = 120 lb : x kg
x = (120 × 0.454) ÷ 1 = 54.48 kg

Length Conversions

Height Conversion

Convert 5 feet 7 inches to centimeters. (1 foot = 30.48 cm, 1 inch = 2.54 cm)

Step-by-Step Solution:

Step 1: Convert feet to cm
5 feet × 30.48 cm/foot = 152.4 cm

Step 2: Convert inches to cm
7 inches × 2.54 cm/inch = 17.78 cm

Step 3: Add together
152.4 cm + 17.78 cm = 170.18 cm ≈ 170 cm

Volume & Speed Conversions

Multiple Conversions

Volume: Gallons to Liters

3 gallons = ? liters
(1 gallon ≈ 3.785 L)
3 × 3.785 = 11.355 L ≈ 11.36 L

Speed: MPH to km/h

60 mph = ? km/h
(1 mile ≈ 1.609 km)
60 × 1.609 = 96.54 km/h ≈ 96.5 km/h

Practice Problems

Problem 1: Temperature

Convert 75°F to Celsius using the formula: C = (F - 32) × 5/9

Your solution:

Problem 2: Distance

A marathon is 26.2 miles. How many kilometers is this? (1 mile ≈ 1.609 km)

Your solution:

Problem 3: Complex Conversion

A recipe calls for 2.5 cups of flour. How many milliliters is this? (1 cup ≈ 236.6 mL)

Your calculation:

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