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Finding the Fourth Proportional to 312.42, 431.15 and 172.55

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Solution

The fourth proportional to 312.42, 431.15 and 172.55 is: 238.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.42 : 431.15 = 172.55 : x
  2. Step 2: Convert to fraction form
    312.42/431.15 = 172.55/x
  3. Step 3: Cross multiply
    312.42x = 431.15 × 172.55
  4. Step 4: Simplify right side
    312.42x = 74,393.21
  5. Step 5: Solve for x
    x = 74,393.21/312.42
  6. Step 6: Final answer
    x = 238.12

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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.