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Finding the Fourth Proportional to 1,139.06, 1,572.13 and 641.71

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Solution

The fourth proportional to 1,139.06, 1,572.13 and 641.71 is: 885.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,139.06 : 1,572.13 = 641.71 : x
  2. Step 2: Convert to fraction form
    1,139.06/1,572.13 = 641.71/x
  3. Step 3: Cross multiply
    1,139.06x = 1,572.13 × 641.71
  4. Step 4: Simplify right side
    1,139.06x = 1,008,853.90
  5. Step 5: Solve for x
    x = 1,008,853.90/1,139.06
  6. Step 6: Final answer
    x = 885.69

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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.