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Finding the Fourth Proportional to 1,314.40, 1,972.60 and 664.78

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Solution

The fourth proportional to 1,314.40, 1,972.60 and 664.78 is: 997.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,314.40 : 1,972.60 = 664.78 : x
  2. Step 2: Convert to fraction form
    1,314.40/1,972.60 = 664.78/x
  3. Step 3: Cross multiply
    1,314.40x = 1,972.60 × 664.78
  4. Step 4: Simplify right side
    1,314.40x = 1,311,345.03
  5. Step 5: Solve for x
    x = 1,311,345.03/1,314.40
  6. Step 6: Final answer
    x = 997.68

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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.