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Finding the Fourth Proportional to 431.64, 648.18 and 261.72

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Solution

The fourth proportional to 431.64, 648.18 and 261.72 is: 393.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.64 : 648.18 = 261.72 : x
  2. Step 2: Convert to fraction form
    431.64/648.18 = 261.72/x
  3. Step 3: Cross multiply
    431.64x = 648.18 × 261.72
  4. Step 4: Simplify right side
    431.64x = 169,641.67
  5. Step 5: Solve for x
    x = 169,641.67/431.64
  6. Step 6: Final answer
    x = 393.02

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.