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Finding the Fourth Proportional to 312.18, 430.78 and 187.85

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Solution

The fourth proportional to 312.18, 430.78 and 187.85 is: 259.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.18 : 430.78 = 187.85 : x
  2. Step 2: Convert to fraction form
    312.18/430.78 = 187.85/x
  3. Step 3: Cross multiply
    312.18x = 430.78 × 187.85
  4. Step 4: Simplify right side
    312.18x = 80,922.02
  5. Step 5: Solve for x
    x = 80,922.02/312.18
  6. Step 6: Final answer
    x = 259.22

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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.