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Finding the Fourth Proportional to 385.55, 531.86 and 261.21

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Solution

The fourth proportional to 385.55, 531.86 and 261.21 is: 360.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    385.55 : 531.86 = 261.21 : x
  2. Step 2: Convert to fraction form
    385.55/531.86 = 261.21/x
  3. Step 3: Cross multiply
    385.55x = 531.86 × 261.21
  4. Step 4: Simplify right side
    385.55x = 138,925.84
  5. Step 5: Solve for x
    x = 138,925.84/385.55
  6. Step 6: Final answer
    x = 360.34

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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.