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Finding the Fourth Proportional to 261.52, 390.41 and 218.20

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Solution

The fourth proportional to 261.52, 390.41 and 218.20 is: 325.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    261.52 : 390.41 = 218.20 : x
  2. Step 2: Convert to fraction form
    261.52/390.41 = 218.20/x
  3. Step 3: Cross multiply
    261.52x = 390.41 × 218.20
  4. Step 4: Simplify right side
    261.52x = 85,187.46
  5. Step 5: Solve for x
    x = 85,187.46/261.52
  6. Step 6: Final answer
    x = 325.74

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.