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Finding the Fourth Proportional to 709.62, 979.30 and 399.12

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Solution

The fourth proportional to 709.62, 979.30 and 399.12 is: 550.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    709.62 : 979.30 = 399.12 : x
  2. Step 2: Convert to fraction form
    709.62/979.30 = 399.12/x
  3. Step 3: Cross multiply
    709.62x = 979.30 × 399.12
  4. Step 4: Simplify right side
    709.62x = 390,858.22
  5. Step 5: Solve for x
    x = 390,858.22/709.62
  6. Step 6: Final answer
    x = 550.80

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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.