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Finding the Fourth Proportional to 712.80, 1,069.86 and 439.43

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Solution

The fourth proportional to 712.80, 1,069.86 and 439.43 is: 659.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    712.80 : 1,069.86 = 439.43 : x
  2. Step 2: Convert to fraction form
    712.80/1,069.86 = 439.43/x
  3. Step 3: Cross multiply
    712.80x = 1,069.86 × 439.43
  4. Step 4: Simplify right side
    712.80x = 470,123.23
  5. Step 5: Solve for x
    x = 470,123.23/712.80
  6. Step 6: Final answer
    x = 659.54

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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.