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Finding the Fourth Proportional to 939.77, 1,406.70 and 645.55

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Solution

The fourth proportional to 939.77, 1,406.70 and 645.55 is: 966.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    939.77 : 1,406.70 = 645.55 : x
  2. Step 2: Convert to fraction form
    939.77/1,406.70 = 645.55/x
  3. Step 3: Cross multiply
    939.77x = 1,406.70 × 645.55
  4. Step 4: Simplify right side
    939.77x = 908,091.67
  5. Step 5: Solve for x
    x = 908,091.67/939.77
  6. Step 6: Final answer
    x = 966.29

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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.