Lesson: Understanding Ratios
1) Mr. Crane’s farm was 45 acres. He fenced â…– of the acres for his cows, then rented â…“ of the remaining acreage to his neighbor. What fractional part of the farm did he rent to his neighbor?
Direct Instruction: (20 minutes)
Review the three ways to write a ratio.
Ex. Derek Jeter of the New York Yankees had 32 hits out of 93 times at bat. Jorge Posada had 11 hits out of 31 times at bat. Are these ratios equivalent? Justify your answer.
Ex. A community pool requires there to be at least 3 lifeguards for every 20 swimmers. There are 60 swimmers and 90 lifeguards. Is this the correct number of lifeguards based on the requirements above? Justify your answer.
Ex. Determine if the two ratios are equivalent:
12 out of 20 doctors agree
10 out of 6 doctors agree
Assessment: (10 minutes)
|ratios and rates work out Assessment||