Interpret and simplify a ratio.

SECTION 1

Historical Context & Motivation

Long ago, people used ratios without knowing the name. Ancient builders in Egypt compared stone blocks to make pyramids strong. They wanted to mix ingredients just right for bread and beer too.

3000 BC

Egyptian Builders

Used ratios for pyramid slopes and recipes. Kept buildings stable for thousands of years.

500 BC

Greek Mathematicians

Euclid wrote about ratios in geometry books. Helped solve problems in shapes and space.

1600s

Modern Math

Ratios became key in maps and art. Artists used them for perfect drawings.

Today

Everyday Use

Ratios help in sports stats and cooking shows. You see them everywhere!

Ratios solved real problems like fair sharing. Now you can use them on the SSAT to compare numbers fast. Get ready to master this skill!

SECTION 2

Core Principles & Definitions

A ratio compares two quantities. It shows how many of one thing for each of another. Think of it like players to balls on a team.

Part-to-Part Ratio

Compares two different groups. Like 3 boys to 4 girls.

Part-to-Whole Ratio

Compares one group to the total. Like 3 boys to 7 kids.

Simplifying Ratios

Divide both numbers by their greatest common factor (GCF). Makes numbers smaller but equal.

Writing Ratios

Use colon (:) or fraction bar. 2:3 means 2 parts to 3 parts.

⚽ KEY TAKEAWAY

Ratios are like a soccer team's score: 2 goals to 1. It tells the story of the game simply. You can simplify your life with them too!

SECTION 3

Visual Explanation

This diagram shows 3 blue circles next to 4 pink squares. The ratio 3:4 compares the groups visually.

See how the shapes make the ratio clear? Blue to pink is 3 to 4. This helps you picture what numbers mean. You are doing great already!

SECTION 4

Mathematical Framework

Ratios use simple math rules. Find the greatest common factor (GCF) to simplify. GCF is the biggest number that divides both parts evenly.

RATIO FORM

a : b = a ÷ d : b ÷ d

where d = GCF(a, b). Example: 6:9, d=3, so 2:3.

FRACTION FORM

a : b = a/b

Simplify fraction by dividing top and bottom by GCF.

Always check if numbers share factors like 2 or 3. This makes ratios easy to compare. Practice makes perfect!

SECTION 5

Detailed Breakdown

Break ratios into steps using tables or lines. This shows equivalent ratios clearly. Like levels in a video game.

Table shows multiples of 2:3. Amber boxes for first part, green for second.

The table proves 4:6 equals 2:3. Multiply or divide by the same number to check. You got this!

SECTION 6

Worked Example

Simplify 12 dogs : 18 cats

Step 1 — Find GCFFactors of 12: 1,2,3,4,6,12. Factors of 18: 1,2,3,6,9,18. GCF is 6.

GCF = 6

Step 2 — Divide Both12 ÷ 6 = 2. 18 ÷ 6 = 3.

2:3

Step 3 — InterpretFor every 2 dogs, there are 3 cats. Perfect pet ratio!

dogs:cats = 2:3

See how easy that was? Follow these steps every time. You will ace SSAT questions like this!

SECTION 7

Strengths & Comparisons

Ratios shine in comparisons. But know when to use fractions too. Let's compare them side by side.

Ratios vs. Fractions

Type	When to Use	Example
Ratio	Compare two groups.	3:4 apples:oranges
Fraction	Part of a whole.	3/7 of class are boys

✦ KEY TAKEAWAY

Ratios are your friends for sharing cookies fairly. Fractions tell how much of the whole plate you get!

SECTION 8

Connection to Advanced Theory

Ratios lead to proportions later. Proportions solve missing parts, like speed problems. You are building a strong base now.

Basic	Advanced
Simplify 4:6 → 2:3	If 2:3 = 4:x, solve x=6
Interpret boys:girls	Rates like 60 miles:2 hours = 30 mph

Master ratios first, then proportions will be easy. Keep practicing—you are on your way!

SECTION 9

Practice Problems

PROBLEM 1 — CONCEPTUAL

What does a ratio compare? A) Two quantities, like red to blue marbles. B) Only whole numbers. C) Addition of numbers. D) The biggest number. E) Subtraction only.

PROBLEM 2 — BASIC CALCULATION

Simplify 4:8. A)1:2 B)2:4 C)4:8 D)1:1 E)8:4

PROBLEM 3 — INTERMEDIATE

Simplify 15:25. A)3:5 B)5:3 C)1:2 D)3:4 E)5:8

PROBLEM 4 — APPLIED

A team has 10 wins and 15 losses. Simplified ratio wins:losses? A)2:3 B)3:2 C)2:5 D)5:2 E)1:1.5

PROBLEM 5 — CRITICAL THINKING

Which ratio is equivalent to 6:9? A)2:3 B)3:6 C)1:2 D)4:6 E)9:6

SUMMARY

Lesson Summary

You learned to interpret ratios as comparisons and simplify by dividing by GCF. Visuals and tables make it fun and clear.

Practice these skills for SSAT success. You are ready to tackle any ratio problem! Great job today.