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Finding the Fourth Proportional to 921.88, 1,381.60 and 511.21

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Solution

The fourth proportional to 921.88, 1,381.60 and 511.21 is: 766.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    921.88 : 1,381.60 = 511.21 : x
  2. Step 2: Convert to fraction form
    921.88/1,381.60 = 511.21/x
  3. Step 3: Cross multiply
    921.88x = 1,381.60 × 511.21
  4. Step 4: Simplify right side
    921.88x = 706,278.27
  5. Step 5: Solve for x
    x = 706,278.27/921.88
  6. Step 6: Final answer
    x = 766.13

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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.