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Finding the Fourth Proportional to 830.71, 1,245.39 and 391.75

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Solution

The fourth proportional to 830.71, 1,245.39 and 391.75 is: 587.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    830.71 : 1,245.39 = 391.75 : x
  2. Step 2: Convert to fraction form
    830.71/1,245.39 = 391.75/x
  3. Step 3: Cross multiply
    830.71x = 1,245.39 × 391.75
  4. Step 4: Simplify right side
    830.71x = 487,876.95
  5. Step 5: Solve for x
    x = 487,876.95/830.71
  6. Step 6: Final answer
    x = 587.30

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.