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Finding the Fourth Proportional to 391.30, 540.21 and 312.36

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Solution

The fourth proportional to 391.30, 540.21 and 312.36 is: 431.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.30 : 540.21 = 312.36 : x
  2. Step 2: Convert to fraction form
    391.30/540.21 = 312.36/x
  3. Step 3: Cross multiply
    391.30x = 540.21 × 312.36
  4. Step 4: Simplify right side
    391.30x = 168,740.00
  5. Step 5: Solve for x
    x = 168,740.00/391.30
  6. Step 6: Final answer
    x = 431.23

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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.