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Finding the Fourth Proportional to 661.80, 990.78 and 539.88

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Solution

The fourth proportional to 661.80, 990.78 and 539.88 is: 808.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.80 : 990.78 = 539.88 : x
  2. Step 2: Convert to fraction form
    661.80/990.78 = 539.88/x
  3. Step 3: Cross multiply
    661.80x = 990.78 × 539.88
  4. Step 4: Simplify right side
    661.80x = 534,902.31
  5. Step 5: Solve for x
    x = 534,902.31/661.80
  6. Step 6: Final answer
    x = 808.25

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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.