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Finding the Fourth Proportional to 858.18, 1,287.20 and 281

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Solution

The fourth proportional to 858.18, 1,287.20 and 281 is: 421.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.18 : 1,287.20 = 281 : x
  2. Step 2: Convert to fraction form
    858.18/1,287.20 = 281/x
  3. Step 3: Cross multiply
    858.18x = 1,287.20 × 281
  4. Step 4: Simplify right side
    858.18x = 361,703.20
  5. Step 5: Solve for x
    x = 361,703.20/858.18
  6. Step 6: Final answer
    x = 421.48

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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.