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Finding the Fourth Proportional to 1,243.54, 1,864.90 and 421.80

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Solution

The fourth proportional to 1,243.54, 1,864.90 and 421.80 is: 632.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,243.54 : 1,864.90 = 421.80 : x
  2. Step 2: Convert to fraction form
    1,243.54/1,864.90 = 421.80/x
  3. Step 3: Cross multiply
    1,243.54x = 1,864.90 × 421.80
  4. Step 4: Simplify right side
    1,243.54x = 786,614.82
  5. Step 5: Solve for x
    x = 786,614.82/1,243.54
  6. Step 6: Final answer
    x = 632.56

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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.