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Finding the Fourth Proportional to 491.28, 678 and 281.46

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Solution

The fourth proportional to 491.28, 678 and 281.46 is: 388.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    491.28 : 678 = 281.46 : x
  2. Step 2: Convert to fraction form
    491.28/678 = 281.46/x
  3. Step 3: Cross multiply
    491.28x = 678 × 281.46
  4. Step 4: Simplify right side
    491.28x = 190,829.88
  5. Step 5: Solve for x
    x = 190,829.88/491.28
  6. Step 6: Final answer
    x = 388.43

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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.