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Finding the Fourth Proportional to 667.86, 921.54 and 388.05

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Solution

The fourth proportional to 667.86, 921.54 and 388.05 is: 535.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    667.86 : 921.54 = 388.05 : x
  2. Step 2: Convert to fraction form
    667.86/921.54 = 388.05/x
  3. Step 3: Cross multiply
    667.86x = 921.54 × 388.05
  4. Step 4: Simplify right side
    667.86x = 357,603.60
  5. Step 5: Solve for x
    x = 357,603.60/667.86
  6. Step 6: Final answer
    x = 535.45

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.