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Finding the Fourth Proportional to 1,288.35, 1,932.18 and 638.91

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Solution

The fourth proportional to 1,288.35, 1,932.18 and 638.91 is: 958.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,288.35 : 1,932.18 = 638.91 : x
  2. Step 2: Convert to fraction form
    1,288.35/1,932.18 = 638.91/x
  3. Step 3: Cross multiply
    1,288.35x = 1,932.18 × 638.91
  4. Step 4: Simplify right side
    1,288.35x = 1,234,489.12
  5. Step 5: Solve for x
    x = 1,234,489.12/1,288.35
  6. Step 6: Final answer
    x = 958.19

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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.