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Finding the Fourth Proportional to 709, 978.42 and 398.56

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Solution

The fourth proportional to 709, 978.42 and 398.56 is: 550.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    709 : 978.42 = 398.56 : x
  2. Step 2: Convert to fraction form
    709/978.42 = 398.56/x
  3. Step 3: Cross multiply
    709x = 978.42 × 398.56
  4. Step 4: Simplify right side
    709x = 389,959.08
  5. Step 5: Solve for x
    x = 389,959.08/709
  6. Step 6: Final answer
    x = 550.01

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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.