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Finding the Fourth Proportional to 261.52, 390.49 and 215.72

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Solution

The fourth proportional to 261.52, 390.49 and 215.72 is: 322.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    261.52 : 390.49 = 215.72 : x
  2. Step 2: Convert to fraction form
    261.52/390.49 = 215.72/x
  3. Step 3: Cross multiply
    261.52x = 390.49 × 215.72
  4. Step 4: Simplify right side
    261.52x = 84,236.50
  5. Step 5: Solve for x
    x = 84,236.50/261.52
  6. Step 6: Final answer
    x = 322.10

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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.