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Finding the Fourth Proportional to 671.28, 1,005.36 and 648.20

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Solution

The fourth proportional to 671.28, 1,005.36 and 648.20 is: 970.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    671.28 : 1,005.36 = 648.20 : x
  2. Step 2: Convert to fraction form
    671.28/1,005.36 = 648.20/x
  3. Step 3: Cross multiply
    671.28x = 1,005.36 × 648.20
  4. Step 4: Simplify right side
    671.28x = 651,674.35
  5. Step 5: Solve for x
    x = 651,674.35/671.28
  6. Step 6: Final answer
    x = 970.79

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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.