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Finding the Fourth Proportional to 857.55, 1,288.05 and 511.56

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Solution

The fourth proportional to 857.55, 1,288.05 and 511.56 is: 768.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.55 : 1,288.05 = 511.56 : x
  2. Step 2: Convert to fraction form
    857.55/1,288.05 = 511.56/x
  3. Step 3: Cross multiply
    857.55x = 1,288.05 × 511.56
  4. Step 4: Simplify right side
    857.55x = 658,916.07
  5. Step 5: Solve for x
    x = 658,916.07/857.55
  6. Step 6: Final answer
    x = 768.37

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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.