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Finding the Fourth Proportional to 491.60, 678.24 and 281.78

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Solution

The fourth proportional to 491.60, 678.24 and 281.78 is: 388.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    491.60 : 678.24 = 281.78 : x
  2. Step 2: Convert to fraction form
    491.60/678.24 = 281.78/x
  3. Step 3: Cross multiply
    491.60x = 678.24 × 281.78
  4. Step 4: Simplify right side
    491.60x = 191,114.47
  5. Step 5: Solve for x
    x = 191,114.47/491.60
  6. Step 6: Final answer
    x = 388.76

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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.