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Finding the Fourth Proportional to 853.58, 1,280.79 and 391.31

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Solution

The fourth proportional to 853.58, 1,280.79 and 391.31 is: 587.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    853.58 : 1,280.79 = 391.31 : x
  2. Step 2: Convert to fraction form
    853.58/1,280.79 = 391.31/x
  3. Step 3: Cross multiply
    853.58x = 1,280.79 × 391.31
  4. Step 4: Simplify right side
    853.58x = 501,185.93
  5. Step 5: Solve for x
    x = 501,185.93/853.58
  6. Step 6: Final answer
    x = 587.16

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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.