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Finding the Fourth Proportional to 321.42, 442.23 and 312.34

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Solution

The fourth proportional to 321.42, 442.23 and 312.34 is: 429.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    321.42 : 442.23 = 312.34 : x
  2. Step 2: Convert to fraction form
    321.42/442.23 = 312.34/x
  3. Step 3: Cross multiply
    321.42x = 442.23 × 312.34
  4. Step 4: Simplify right side
    321.42x = 138,126.12
  5. Step 5: Solve for x
    x = 138,126.12/321.42
  6. Step 6: Final answer
    x = 429.74

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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.