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Finding the Fourth Proportional to 385.12, 531.60 and 286.72

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Solution

The fourth proportional to 385.12, 531.60 and 286.72 is: 395.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    385.12 : 531.60 = 286.72 : x
  2. Step 2: Convert to fraction form
    385.12/531.60 = 286.72/x
  3. Step 3: Cross multiply
    385.12x = 531.60 × 286.72
  4. Step 4: Simplify right side
    385.12x = 152,420.35
  5. Step 5: Solve for x
    x = 152,420.35/385.12
  6. Step 6: Final answer
    x = 395.77

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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.