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Finding the Fourth Proportional to 391.78, 540.39 and 261.01

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Solution

The fourth proportional to 391.78, 540.39 and 261.01 is: 360.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.78 : 540.39 = 261.01 : x
  2. Step 2: Convert to fraction form
    391.78/540.39 = 261.01/x
  3. Step 3: Cross multiply
    391.78x = 540.39 × 261.01
  4. Step 4: Simplify right side
    391.78x = 141,047.19
  5. Step 5: Solve for x
    x = 141,047.19/391.78
  6. Step 6: Final answer
    x = 360.02

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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.