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Finding the Fourth Proportional to 1,287.13, 1,930.78 and 637.69

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Solution

The fourth proportional to 1,287.13, 1,930.78 and 637.69 is: 956.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287.13 : 1,930.78 = 637.69 : x
  2. Step 2: Convert to fraction form
    1,287.13/1,930.78 = 637.69/x
  3. Step 3: Cross multiply
    1,287.13x = 1,930.78 × 637.69
  4. Step 4: Simplify right side
    1,287.13x = 1,231,239.10
  5. Step 5: Solve for x
    x = 1,231,239.10/1,287.13
  6. Step 6: Final answer
    x = 956.58

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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.