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Finding the Fourth Proportional to 515.78, 711.66 and 291.72

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Solution

The fourth proportional to 515.78, 711.66 and 291.72 is: 402.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    515.78 : 711.66 = 291.72 : x
  2. Step 2: Convert to fraction form
    515.78/711.66 = 291.72/x
  3. Step 3: Cross multiply
    515.78x = 711.66 × 291.72
  4. Step 4: Simplify right side
    515.78x = 207,607.76
  5. Step 5: Solve for x
    x = 207,607.76/515.78
  6. Step 6: Final answer
    x = 402.51

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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.