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Finding the Fourth Proportional to 709.55, 979.19 and 399.05

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Solution

The fourth proportional to 709.55, 979.19 and 399.05 is: 550.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    709.55 : 979.19 = 399.05 : x
  2. Step 2: Convert to fraction form
    709.55/979.19 = 399.05/x
  3. Step 3: Cross multiply
    709.55x = 979.19 × 399.05
  4. Step 4: Simplify right side
    709.55x = 390,745.77
  5. Step 5: Solve for x
    x = 390,745.77/709.55
  6. Step 6: Final answer
    x = 550.70

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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.