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Finding the Fourth Proportional to 661.87, 990.42 and 415.18

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Solution

The fourth proportional to 661.87, 990.42 and 415.18 is: 621.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.87 : 990.42 = 415.18 : x
  2. Step 2: Convert to fraction form
    661.87/990.42 = 415.18/x
  3. Step 3: Cross multiply
    661.87x = 990.42 × 415.18
  4. Step 4: Simplify right side
    661.87x = 411,202.58
  5. Step 5: Solve for x
    x = 411,202.58/661.87
  6. Step 6: Final answer
    x = 621.27

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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.