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Finding the Fourth Proportional to 1,139.79, 1,572.86 and 667.70

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Solution

The fourth proportional to 1,139.79, 1,572.86 and 667.70 is: 921.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,139.79 : 1,572.86 = 667.70 : x
  2. Step 2: Convert to fraction form
    1,139.79/1,572.86 = 667.70/x
  3. Step 3: Cross multiply
    1,139.79x = 1,572.86 × 667.70
  4. Step 4: Simplify right side
    1,139.79x = 1,050,198.62
  5. Step 5: Solve for x
    x = 1,050,198.62/1,139.79
  6. Step 6: Final answer
    x = 921.40

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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.