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Finding the Fourth Proportional to 759.75, 1,139.15 and 320.78

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Solution

The fourth proportional to 759.75, 1,139.15 and 320.78 is: 480.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    759.75 : 1,139.15 = 320.78 : x
  2. Step 2: Convert to fraction form
    759.75/1,139.15 = 320.78/x
  3. Step 3: Cross multiply
    759.75x = 1,139.15 × 320.78
  4. Step 4: Simplify right side
    759.75x = 365,412.06
  5. Step 5: Solve for x
    x = 365,412.06/759.75
  6. Step 6: Final answer
    x = 480.96

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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.