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Finding the Fourth Proportional to 391.80, 540.35 and 386.94

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Solution

The fourth proportional to 391.80, 540.35 and 386.94 is: 533.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.80 : 540.35 = 386.94 : x
  2. Step 2: Convert to fraction form
    391.80/540.35 = 386.94/x
  3. Step 3: Cross multiply
    391.80x = 540.35 × 386.94
  4. Step 4: Simplify right side
    391.80x = 209,083.03
  5. Step 5: Solve for x
    x = 209,083.03/391.80
  6. Step 6: Final answer
    x = 533.65

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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.