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Finding the Fourth Proportional to 491.51, 678.31 and 281.68

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Solution

The fourth proportional to 491.51, 678.31 and 281.68 is: 388.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    491.51 : 678.31 = 281.68 : x
  2. Step 2: Convert to fraction form
    491.51/678.31 = 281.68/x
  3. Step 3: Cross multiply
    491.51x = 678.31 × 281.68
  4. Step 4: Simplify right side
    491.51x = 191,063.96
  5. Step 5: Solve for x
    x = 191,063.96/491.51
  6. Step 6: Final answer
    x = 388.73

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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.