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Finding the Fourth Proportional to 491.39, 678.14 and 281.60

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Solution

The fourth proportional to 491.39, 678.14 and 281.60 is: 388.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    491.39 : 678.14 = 281.60 : x
  2. Step 2: Convert to fraction form
    491.39/678.14 = 281.60/x
  3. Step 3: Cross multiply
    491.39x = 678.14 × 281.60
  4. Step 4: Simplify right side
    491.39x = 190,964.22
  5. Step 5: Solve for x
    x = 190,964.22/491.39
  6. Step 6: Final answer
    x = 388.62

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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.