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Finding the Fourth Proportional to 312.12, 430.35 and 255.91

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Solution

The fourth proportional to 312.12, 430.35 and 255.91 is: 352.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.12 : 430.35 = 255.91 : x
  2. Step 2: Convert to fraction form
    312.12/430.35 = 255.91/x
  3. Step 3: Cross multiply
    312.12x = 430.35 × 255.91
  4. Step 4: Simplify right side
    312.12x = 110,130.87
  5. Step 5: Solve for x
    x = 110,130.87/312.12
  6. Step 6: Final answer
    x = 352.85

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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.