Lesson 3.73.5 · 3.6 · 3.7 · 3.9 Catch-Up
Start hereWords, worked example, and sentence starters
Learning target I can show I am caught up on Lessons 3.5 · 3.6 · 3.7 · 3.9 by using each lesson's big idea in mixed practice.
Start hereWords for this lesson
Read each word before you begin. Say it out loud.
| Word | What it means | Example |
|---|---|---|
| Compare RatiosSpanish: Comparar razones | Decide which ratio is greater, less, or equal by using equivalent ratios or unit rates. | Compare 6:2 and 8:4 using unit rates: 3 > 2. |
| Unit rateSpanish: Tasa unitaria | A rate for just 1 of something, like cost for 1 item. | $3 per 1 pound → unit rate is $3/lb |
| Equivalent ratioSpanish: Razón equivalente | Two ratios that mean the same thing. | 4:6 and 2:3 are equivalent (both simplify to 2:3) |
| CompareSpanish: Comparar | To look at ratios and see which is bigger, smaller, or equal. | 3:4 vs. 2:5 — which has more of the first ingredient per unit? |
| SimplifySpanish: Simplificar | To write a ratio with smaller numbers that still compares the same way. 6:8 and 3:4 are the same ratio. | 8:12 → divide both by 4 → 2:3 |
| Common denominatorSpanish: Denominador común | A bottom number that two fractions can share so you can compare them. | To compare 3/5 and 4/7, use LCD 35: 21/35 vs 20/35 |
How it worksWorked exampleconverting across the two systems
These numbers are not on your problems. The steps are. Follow them with your own numbers.
A room is 5 meters wide. How many feet is that? (1 meter ≈ 3.28 feet)
- Write the conversion factor. 1 m ≈ 3.28 ft
- Ask which unit is BIGGER. A meter is bigger than a foot.
- A bigger unit becomes MORE of the smaller unit, so multiply. 5 × 3.28 = 16.4
- Check reasonableness: 16.4 ft is more than 5 — correct direction. ✓
Answer: 5 meters ≈ 16.4 feet.
Now you trySame steps, your turn
The steps are the same as the worked example. The numbers are yours. Do the work.
A crate weighs 12 kilograms. How many pounds is that? (1 kg ≈ 2.2 lbs)
- Write the conversion factor. 1 kg ≈ lbs
- Which unit is bigger, a kilogram or a pound?
- Bigger unit → more of the smaller unit, so .
- Compute and check. 12 × ≈ lbs
Say it and write itSentence starters
Finish each sentence out loud with a partner. Then use them in your writing.
- I know 1 ≈ .
- A is bigger than a , so I .
- My answer is about .
- This is reasonable because .
Word bank convertconversion factorapproximatelyaboutreasonablebiggersmallermultiplydividemetermilekilogram
Watch outA common mistake
A common mistake in Equivalent Ratios is ADDING the scale factor to one part instead of MULTIPLYING both parts by it. For example, scaling 2:5 by a factor of 4 should give 8:20 (2×4 and 5×4) — not 6:9 (2+4 and 5+4). Adding changes the taste of the recipe (and the value of the ratio); only multiplying or dividing both numbers by the same amount keeps it equivalent.
Lesson 3.73.5 · 3.6 · 3.7 · 3.9 Catch-Up
Catch-UpSkill bridge
Learning target I can show I am caught up on Lessons 3.5 · 3.6 · 3.7 · 3.9 by using each lesson's big idea in mixed practice.
-
1Circle the letter of the best answer. Show how you know.
(Lesson 3.5) Chef A uses 2 cups of cheese for every 8 crackers. Chef B uses 3 cups of cheese for every 9 crackers. Who uses more cheese per cracker?
- AChef B
- BChef A
- CThey use the same amount
- DCannot determine
Hint You can't compare 2 cups and 3 cups directly — the chefs use different numbers of crackers.
Show your work -
2Circle the letter of the best answer. Show how you know.
(Lesson 3.5) Which ratio is greater: 3:4 or 5:8?
- A5:8
- BThey are equal
- C3:4
- DCannot determine
Hint The second numbers (4 and 8) don't match, so the ratios aren't ready to compare yet.
Show your work -
3Circle the letter of the best answer. Show how you know.
(Lesson 3.6) There are 12 inches in 1 foot. How many inches are in 5 feet?
- A7 inches
- B17 inches
- C50 inches
- D60 inches
Hint Write the unit ratio first: 12 inches : 1 foot.
Show your work -
4Circle the letter of the best answer. Show how you know.
(Lesson 3.6) There are 1,000 milliliters in 1 liter. How many milliliters are in 3 liters?
- A30 mL
- B300 mL
- C1,003 mL
- D3,000 mL
Hint The unit ratio is 1,000 mL : 1 L.
Show your work -
5Circle the letter of the best answer. Show how you know.
(Lesson 3.7) 1 kilometer ≈ 0.6 mile. About how many miles is 5 kilometers?
- A3 miles
- B5.6 miles
- C8 miles
- D30 miles
Hint Write the conversion factor as a ratio: 1 : 0.6.
Show your work
Explain your thinkingHow did you find the missing values in Chef Montoya's table? How can you PROVE two of your rows are equivalent ratios?
Sentence starter I multiplied ___ and ___ by the same number, ___, so the ratio ___ is equivalent to 3:2.