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Finding the Fourth Proportional to 287.78, 397.11 and 156.78

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Solution

The fourth proportional to 287.78, 397.11 and 156.78 is: 216.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.78 : 397.11 = 156.78 : x
  2. Step 2: Convert to fraction form
    287.78/397.11 = 156.78/x
  3. Step 3: Cross multiply
    287.78x = 397.11 × 156.78
  4. Step 4: Simplify right side
    287.78x = 62,258.91
  5. Step 5: Solve for x
    x = 62,258.91/287.78
  6. Step 6: Final answer
    x = 216.35

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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.