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Finding the Fourth Proportional to 714.28, 985.64 and 399.53

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Solution

The fourth proportional to 714.28, 985.64 and 399.53 is: 551.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    714.28 : 985.64 = 399.53 : x
  2. Step 2: Convert to fraction form
    714.28/985.64 = 399.53/x
  3. Step 3: Cross multiply
    714.28x = 985.64 × 399.53
  4. Step 4: Simplify right side
    714.28x = 393,791.28
  5. Step 5: Solve for x
    x = 393,791.28/714.28
  6. Step 6: Final answer
    x = 551.31

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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.