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Finding the Fourth Proportional to 456.78, 685.20 and 148.80

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Solution

The fourth proportional to 456.78, 685.20 and 148.80 is: 223.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    456.78 : 685.20 = 148.80 : x
  2. Step 2: Convert to fraction form
    456.78/685.20 = 148.80/x
  3. Step 3: Cross multiply
    456.78x = 685.20 × 148.80
  4. Step 4: Simplify right side
    456.78x = 101,957.76
  5. Step 5: Solve for x
    x = 101,957.76/456.78
  6. Step 6: Final answer
    x = 223.21

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.