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Finding the Fourth Proportional to 691.79, 1,038.07 and 280.89

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Solution

The fourth proportional to 691.79, 1,038.07 and 280.89 is: 421.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    691.79 : 1,038.07 = 280.89 : x
  2. Step 2: Convert to fraction form
    691.79/1,038.07 = 280.89/x
  3. Step 3: Cross multiply
    691.79x = 1,038.07 × 280.89
  4. Step 4: Simplify right side
    691.79x = 291,585.17
  5. Step 5: Solve for x
    x = 291,585.17/691.79
  6. Step 6: Final answer
    x = 421.49

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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.