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Finding the Fourth Proportional to 709.55, 979.19 and 390.54

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Solution

The fourth proportional to 709.55, 979.19 and 390.54 is: 538.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    709.55 : 979.19 = 390.54 : x
  2. Step 2: Convert to fraction form
    709.55/979.19 = 390.54/x
  3. Step 3: Cross multiply
    709.55x = 979.19 × 390.54
  4. Step 4: Simplify right side
    709.55x = 382,412.86
  5. Step 5: Solve for x
    x = 382,412.86/709.55
  6. Step 6: Final answer
    x = 538.95

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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.