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Finding the Fourth Proportional to 669.65, 1,003.55 and 611.78

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Solution

The fourth proportional to 669.65, 1,003.55 and 611.78 is: 916.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    669.65 : 1,003.55 = 611.78 : x
  2. Step 2: Convert to fraction form
    669.65/1,003.55 = 611.78/x
  3. Step 3: Cross multiply
    669.65x = 1,003.55 × 611.78
  4. Step 4: Simplify right side
    669.65x = 613,943.74
  5. Step 5: Solve for x
    x = 613,943.74/669.65
  6. Step 6: Final answer
    x = 916.82

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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.