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Finding the Fourth Proportional to 858.31, 1,287.56 and 281.23

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Solution

The fourth proportional to 858.31, 1,287.56 and 281.23 is: 421.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.31 : 1,287.56 = 281.23 : x
  2. Step 2: Convert to fraction form
    858.31/1,287.56 = 281.23/x
  3. Step 3: Cross multiply
    858.31x = 1,287.56 × 281.23
  4. Step 4: Simplify right side
    858.31x = 362,099.09
  5. Step 5: Solve for x
    x = 362,099.09/858.31
  6. Step 6: Final answer
    x = 421.87

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.