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Finding the Fourth Proportional to 661.19, 990.42 and 478.94

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Solution

The fourth proportional to 661.19, 990.42 and 478.94 is: 717.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.19 : 990.42 = 478.94 : x
  2. Step 2: Convert to fraction form
    661.19/990.42 = 478.94/x
  3. Step 3: Cross multiply
    661.19x = 990.42 × 478.94
  4. Step 4: Simplify right side
    661.19x = 474,351.75
  5. Step 5: Solve for x
    x = 474,351.75/661.19
  6. Step 6: Final answer
    x = 717.42

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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.