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Finding the Fourth Proportional to 1,287.63, 1,930.10 and 670.68

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Solution

The fourth proportional to 1,287.63, 1,930.10 and 670.68 is: 1,005.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287.63 : 1,930.10 = 670.68 : x
  2. Step 2: Convert to fraction form
    1,287.63/1,930.10 = 670.68/x
  3. Step 3: Cross multiply
    1,287.63x = 1,930.10 × 670.68
  4. Step 4: Simplify right side
    1,287.63x = 1,294,476.11
  5. Step 5: Solve for x
    x = 1,294,476.11/1,287.63
  6. Step 6: Final answer
    x = 1,005.32

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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.