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Finding the Fourth Proportional to 714.42, 985.79 and 399.70

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Solution

The fourth proportional to 714.42, 985.79 and 399.70 is: 551.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    714.42 : 985.79 = 399.70 : x
  2. Step 2: Convert to fraction form
    714.42/985.79 = 399.70/x
  3. Step 3: Cross multiply
    714.42x = 985.79 × 399.70
  4. Step 4: Simplify right side
    714.42x = 394,020.26
  5. Step 5: Solve for x
    x = 394,020.26/714.42
  6. Step 6: Final answer
    x = 551.52

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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.