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Finding the Fourth Proportional to 1,287.68, 1,930.34 and 670.65

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Solution

The fourth proportional to 1,287.68, 1,930.34 and 670.65 is: 1,005.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287.68 : 1,930.34 = 670.65 : x
  2. Step 2: Convert to fraction form
    1,287.68/1,930.34 = 670.65/x
  3. Step 3: Cross multiply
    1,287.68x = 1,930.34 × 670.65
  4. Step 4: Simplify right side
    1,287.68x = 1,294,579.17
  5. Step 5: Solve for x
    x = 1,294,579.17/1,287.68
  6. Step 6: Final answer
    x = 1,005.36

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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.