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Finding the Fourth Proportional to 670.28, 1,005.42 and 285.56

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Solution

The fourth proportional to 670.28, 1,005.42 and 285.56 is: 428.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    670.28 : 1,005.42 = 285.56 : x
  2. Step 2: Convert to fraction form
    670.28/1,005.42 = 285.56/x
  3. Step 3: Cross multiply
    670.28x = 1,005.42 × 285.56
  4. Step 4: Simplify right side
    670.28x = 287,107.74
  5. Step 5: Solve for x
    x = 287,107.74/670.28
  6. Step 6: Final answer
    x = 428.34

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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.