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Finding the Fourth Proportional to 714.39, 985.81 and 399.68

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Solution

The fourth proportional to 714.39, 985.81 and 399.68 is: 551.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    714.39 : 985.81 = 399.68 : x
  2. Step 2: Convert to fraction form
    714.39/985.81 = 399.68/x
  3. Step 3: Cross multiply
    714.39x = 985.81 × 399.68
  4. Step 4: Simplify right side
    714.39x = 394,008.54
  5. Step 5: Solve for x
    x = 394,008.54/714.39
  6. Step 6: Final answer
    x = 551.53

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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.