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Finding the Fourth Proportional to 709.72, 979.38 and 399.16

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Solution

The fourth proportional to 709.72, 979.38 and 399.16 is: 550.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    709.72 : 979.38 = 399.16 : x
  2. Step 2: Convert to fraction form
    709.72/979.38 = 399.16/x
  3. Step 3: Cross multiply
    709.72x = 979.38 × 399.16
  4. Step 4: Simplify right side
    709.72x = 390,929.32
  5. Step 5: Solve for x
    x = 390,929.32/709.72
  6. Step 6: Final answer
    x = 550.82

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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.