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Finding the Fourth Proportional to 759.70, 1,139.82 and 638.20

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Solution

The fourth proportional to 759.70, 1,139.82 and 638.20 is: 957.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    759.70 : 1,139.82 = 638.20 : x
  2. Step 2: Convert to fraction form
    759.70/1,139.82 = 638.20/x
  3. Step 3: Cross multiply
    759.70x = 1,139.82 × 638.20
  4. Step 4: Simplify right side
    759.70x = 727,433.12
  5. Step 5: Solve for x
    x = 727,433.12/759.70
  6. Step 6: Final answer
    x = 957.53

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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.