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Finding the Fourth Proportional to 1,280.56, 1,921.02 and 511

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Solution

The fourth proportional to 1,280.56, 1,921.02 and 511 is: 766.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,280.56 : 1,921.02 = 511 : x
  2. Step 2: Convert to fraction form
    1,280.56/1,921.02 = 511/x
  3. Step 3: Cross multiply
    1,280.56x = 1,921.02 × 511
  4. Step 4: Simplify right side
    1,280.56x = 981,641.22
  5. Step 5: Solve for x
    x = 981,641.22/1,280.56
  6. Step 6: Final answer
    x = 766.57

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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.