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Finding the Fourth Proportional to 691.64, 1,037.36 and 280.78

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Solution

The fourth proportional to 691.64, 1,037.36 and 280.78 is: 421.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    691.64 : 1,037.36 = 280.78 : x
  2. Step 2: Convert to fraction form
    691.64/1,037.36 = 280.78/x
  3. Step 3: Cross multiply
    691.64x = 1,037.36 × 280.78
  4. Step 4: Simplify right side
    691.64x = 291,264.75
  5. Step 5: Solve for x
    x = 291,264.75/691.64
  6. Step 6: Final answer
    x = 421.12

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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.