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Finding the Fourth Proportional to 660.78, 990.99 and 331.74

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Solution

The fourth proportional to 660.78, 990.99 and 331.74 is: 497.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    660.78 : 990.99 = 331.74 : x
  2. Step 2: Convert to fraction form
    660.78/990.99 = 331.74/x
  3. Step 3: Cross multiply
    660.78x = 990.99 × 331.74
  4. Step 4: Simplify right side
    660.78x = 328,751.02
  5. Step 5: Solve for x
    x = 328,751.02/660.78
  6. Step 6: Final answer
    x = 497.52

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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.