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Finding the Fourth Proportional to 431.76, 648.64 and 258.88

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Solution

The fourth proportional to 431.76, 648.64 and 258.88 is: 388.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.76 : 648.64 = 258.88 : x
  2. Step 2: Convert to fraction form
    431.76/648.64 = 258.88/x
  3. Step 3: Cross multiply
    431.76x = 648.64 × 258.88
  4. Step 4: Simplify right side
    431.76x = 167,919.92
  5. Step 5: Solve for x
    x = 167,919.92/431.76
  6. Step 6: Final answer
    x = 388.92

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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.