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Finding the Fourth Proportional to 312.18, 430.79 and 172.31

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Solution

The fourth proportional to 312.18, 430.79 and 172.31 is: 237.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.18 : 430.79 = 172.31 : x
  2. Step 2: Convert to fraction form
    312.18/430.79 = 172.31/x
  3. Step 3: Cross multiply
    312.18x = 430.79 × 172.31
  4. Step 4: Simplify right side
    312.18x = 74,226.41
  5. Step 5: Solve for x
    x = 74,226.41/312.18
  6. Step 6: Final answer
    x = 237.77

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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.