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Finding the Fourth Proportional to 491.69, 678.49 and 281.86

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Solution

The fourth proportional to 491.69, 678.49 and 281.86 is: 388.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    491.69 : 678.49 = 281.86 : x
  2. Step 2: Convert to fraction form
    491.69/678.49 = 281.86/x
  3. Step 3: Cross multiply
    491.69x = 678.49 × 281.86
  4. Step 4: Simplify right side
    491.69x = 191,239.19
  5. Step 5: Solve for x
    x = 191,239.19/491.69
  6. Step 6: Final answer
    x = 388.95

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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.