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Finding the Fourth Proportional to 709.16, 978.58 and 398.68

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Solution

The fourth proportional to 709.16, 978.58 and 398.68 is: 550.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    709.16 : 978.58 = 398.68 : x
  2. Step 2: Convert to fraction form
    709.16/978.58 = 398.68/x
  3. Step 3: Cross multiply
    709.16x = 978.58 × 398.68
  4. Step 4: Simplify right side
    709.16x = 390,140.27
  5. Step 5: Solve for x
    x = 390,140.27/709.16
  6. Step 6: Final answer
    x = 550.14

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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.