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Finding the Fourth Proportional to 391.37, 540.30 and 312.42

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Solution

The fourth proportional to 391.37, 540.30 and 312.42 is: 431.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.37 : 540.30 = 312.42 : x
  2. Step 2: Convert to fraction form
    391.37/540.30 = 312.42/x
  3. Step 3: Cross multiply
    391.37x = 540.30 × 312.42
  4. Step 4: Simplify right side
    391.37x = 168,803.72
  5. Step 5: Solve for x
    x = 168,803.72/391.37
  6. Step 6: Final answer
    x = 431.32

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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.