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Finding the Fourth Proportional to 667.64, 921.15 and 428.45

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Solution

The fourth proportional to 667.64, 921.15 and 428.45 is: 591.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    667.64 : 921.15 = 428.45 : x
  2. Step 2: Convert to fraction form
    667.64/921.15 = 428.45/x
  3. Step 3: Cross multiply
    667.64x = 921.15 × 428.45
  4. Step 4: Simplify right side
    667.64x = 394,662.11
  5. Step 5: Solve for x
    x = 394,662.11/667.64
  6. Step 6: Final answer
    x = 591.13

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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.