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Finding the Fourth Proportional to 714.28, 985.65 and 403.78

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Solution

The fourth proportional to 714.28, 985.65 and 403.78 is: 557.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    714.28 : 985.65 = 403.78 : x
  2. Step 2: Convert to fraction form
    714.28/985.65 = 403.78/x
  3. Step 3: Cross multiply
    714.28x = 985.65 × 403.78
  4. Step 4: Simplify right side
    714.28x = 397,985.76
  5. Step 5: Solve for x
    x = 397,985.76/714.28
  6. Step 6: Final answer
    x = 557.18

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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.