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Finding the Fourth Proportional to 1,280.75, 1,921.73 and 631.13

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Solution

The fourth proportional to 1,280.75, 1,921.73 and 631.13 is: 946.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,280.75 : 1,921.73 = 631.13 : x
  2. Step 2: Convert to fraction form
    1,280.75/1,921.73 = 631.13/x
  3. Step 3: Cross multiply
    1,280.75x = 1,921.73 × 631.13
  4. Step 4: Simplify right side
    1,280.75x = 1,212,861.45
  5. Step 5: Solve for x
    x = 1,212,861.45/1,280.75
  6. Step 6: Final answer
    x = 946.99

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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.