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Finding the Fourth Proportional to 640.65, 883.81 and 391.93

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Solution

The fourth proportional to 640.65, 883.81 and 391.93 is: 540.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.65 : 883.81 = 391.93 : x
  2. Step 2: Convert to fraction form
    640.65/883.81 = 391.93/x
  3. Step 3: Cross multiply
    640.65x = 883.81 × 391.93
  4. Step 4: Simplify right side
    640.65x = 346,389.93
  5. Step 5: Solve for x
    x = 346,389.93/640.65
  6. Step 6: Final answer
    x = 540.68

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.