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Finding the Fourth Proportional to 714.05, 985.38 and 399.31

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Solution

The fourth proportional to 714.05, 985.38 and 399.31 is: 551.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    714.05 : 985.38 = 399.31 : x
  2. Step 2: Convert to fraction form
    714.05/985.38 = 399.31/x
  3. Step 3: Cross multiply
    714.05x = 985.38 × 399.31
  4. Step 4: Simplify right side
    714.05x = 393,477.76
  5. Step 5: Solve for x
    x = 393,477.76/714.05
  6. Step 6: Final answer
    x = 551.05

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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.