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Finding the Fourth Proportional to 1,318.31, 1,979.28 and 669.50

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Solution

The fourth proportional to 1,318.31, 1,979.28 and 669.50 is: 1,005.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,318.31 : 1,979.28 = 669.50 : x
  2. Step 2: Convert to fraction form
    1,318.31/1,979.28 = 669.50/x
  3. Step 3: Cross multiply
    1,318.31x = 1,979.28 × 669.50
  4. Step 4: Simplify right side
    1,318.31x = 1,325,118.06
  5. Step 5: Solve for x
    x = 1,325,118.06/1,318.31
  6. Step 6: Final answer
    x = 1,005.17

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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.