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Finding the Fourth Proportional to 667.55, 921.17 and 387.77

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Solution

The fourth proportional to 667.55, 921.17 and 387.77 is: 535.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    667.55 : 921.17 = 387.77 : x
  2. Step 2: Convert to fraction form
    667.55/921.17 = 387.77/x
  3. Step 3: Cross multiply
    667.55x = 921.17 × 387.77
  4. Step 4: Simplify right side
    667.55x = 357,195.55
  5. Step 5: Solve for x
    x = 357,195.55/667.55
  6. Step 6: Final answer
    x = 535.09

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1.5x scale

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.