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Finding the Fourth Proportional to 709.56, 979.08 and 399

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Solution

The fourth proportional to 709.56, 979.08 and 399 is: 550.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    709.56 : 979.08 = 399 : x
  2. Step 2: Convert to fraction form
    709.56/979.08 = 399/x
  3. Step 3: Cross multiply
    709.56x = 979.08 × 399
  4. Step 4: Simplify right side
    709.56x = 390,652.92
  5. Step 5: Solve for x
    x = 390,652.92/709.56
  6. Step 6: Final answer
    x = 550.56

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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.