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Finding the Fourth Proportional to 309.12, 426.18 and 285.66

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Solution

The fourth proportional to 309.12, 426.18 and 285.66 is: 393.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.12 : 426.18 = 285.66 : x
  2. Step 2: Convert to fraction form
    309.12/426.18 = 285.66/x
  3. Step 3: Cross multiply
    309.12x = 426.18 × 285.66
  4. Step 4: Simplify right side
    309.12x = 121,742.58
  5. Step 5: Solve for x
    x = 121,742.58/309.12
  6. Step 6: Final answer
    x = 393.84

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.