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Finding the Fourth Proportional to 515.78, 711.22 and 390.02

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Solution

The fourth proportional to 515.78, 711.22 and 390.02 is: 537.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    515.78 : 711.22 = 390.02 : x
  2. Step 2: Convert to fraction form
    515.78/711.22 = 390.02/x
  3. Step 3: Cross multiply
    515.78x = 711.22 × 390.02
  4. Step 4: Simplify right side
    515.78x = 277,390.83
  5. Step 5: Solve for x
    x = 277,390.83/515.78
  6. Step 6: Final answer
    x = 537.81

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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.