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Finding the Fourth Proportional to 709.17, 978.79 and 398.67

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Solution

The fourth proportional to 709.17, 978.79 and 398.67 is: 550.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    709.17 : 978.79 = 398.67 : x
  2. Step 2: Convert to fraction form
    709.17/978.79 = 398.67/x
  3. Step 3: Cross multiply
    709.17x = 978.79 × 398.67
  4. Step 4: Simplify right side
    709.17x = 390,216.92
  5. Step 5: Solve for x
    x = 390,216.92/709.17
  6. Step 6: Final answer
    x = 550.24

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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.