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Finding the Fourth Proportional to 1,280.55, 1,921.05 and 631.28

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Solution

The fourth proportional to 1,280.55, 1,921.05 and 631.28 is: 947.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,280.55 : 1,921.05 = 631.28 : x
  2. Step 2: Convert to fraction form
    1,280.55/1,921.05 = 631.28/x
  3. Step 3: Cross multiply
    1,280.55x = 1,921.05 × 631.28
  4. Step 4: Simplify right side
    1,280.55x = 1,212,720.44
  5. Step 5: Solve for x
    x = 1,212,720.44/1,280.55
  6. Step 6: Final answer
    x = 947.03

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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.