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Finding the Fourth Proportional to 853.79, 1,281.71 and 391.68

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Solution

The fourth proportional to 853.79, 1,281.71 and 391.68 is: 587.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    853.79 : 1,281.71 = 391.68 : x
  2. Step 2: Convert to fraction form
    853.79/1,281.71 = 391.68/x
  3. Step 3: Cross multiply
    853.79x = 1,281.71 × 391.68
  4. Step 4: Simplify right side
    853.79x = 502,021.15
  5. Step 5: Solve for x
    x = 502,021.15/853.79
  6. Step 6: Final answer
    x = 587.99

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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.