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Finding the Fourth Proportional to 309.40, 426.61 and 231.64

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Solution

The fourth proportional to 309.40, 426.61 and 231.64 is: 319.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.40 : 426.61 = 231.64 : x
  2. Step 2: Convert to fraction form
    309.40/426.61 = 231.64/x
  3. Step 3: Cross multiply
    309.40x = 426.61 × 231.64
  4. Step 4: Simplify right side
    309.40x = 98,817.81
  5. Step 5: Solve for x
    x = 98,817.81/309.40
  6. Step 6: Final answer
    x = 319.39

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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.