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Finding the Fourth Proportional to 312.14, 430.74 and 187.78

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Solution

The fourth proportional to 312.14, 430.74 and 187.78 is: 259.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.14 : 430.74 = 187.78 : x
  2. Step 2: Convert to fraction form
    312.14/430.74 = 187.78/x
  3. Step 3: Cross multiply
    312.14x = 430.74 × 187.78
  4. Step 4: Simplify right side
    312.14x = 80,881.26
  5. Step 5: Solve for x
    x = 80,881.26/312.14
  6. Step 6: Final answer
    x = 259.12

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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.