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Finding the Fourth Proportional to 660.88, 991.32 and 285.60

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Solution

The fourth proportional to 660.88, 991.32 and 285.60 is: 428.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    660.88 : 991.32 = 285.60 : x
  2. Step 2: Convert to fraction form
    660.88/991.32 = 285.60/x
  3. Step 3: Cross multiply
    660.88x = 991.32 × 285.60
  4. Step 4: Simplify right side
    660.88x = 283,116.76
  5. Step 5: Solve for x
    x = 283,116.76/660.88
  6. Step 6: Final answer
    x = 428.40

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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.