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Finding the Fourth Proportional to 920.59, 1,269.79 and 640.87

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Solution

The fourth proportional to 920.59, 1,269.79 and 640.87 is: 883.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    920.59 : 1,269.79 = 640.87 : x
  2. Step 2: Convert to fraction form
    920.59/1,269.79 = 640.87/x
  3. Step 3: Cross multiply
    920.59x = 1,269.79 × 640.87
  4. Step 4: Simplify right side
    920.59x = 813,770.32
  5. Step 5: Solve for x
    x = 813,770.32/920.59
  6. Step 6: Final answer
    x = 883.97

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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.