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Finding the Fourth Proportional to 854.42, 1,281.19 and 391.80

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Solution

The fourth proportional to 854.42, 1,281.19 and 391.80 is: 587.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    854.42 : 1,281.19 = 391.80 : x
  2. Step 2: Convert to fraction form
    854.42/1,281.19 = 391.80/x
  3. Step 3: Cross multiply
    854.42x = 1,281.19 × 391.80
  4. Step 4: Simplify right side
    854.42x = 501,969.26
  5. Step 5: Solve for x
    x = 501,969.26/854.42
  6. Step 6: Final answer
    x = 587.50

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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.