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Finding the Fourth Proportional to 661.20, 990 and 372.24

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Solution

The fourth proportional to 661.20, 990 and 372.24 is: 557.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.20 : 990 = 372.24 : x
  2. Step 2: Convert to fraction form
    661.20/990 = 372.24/x
  3. Step 3: Cross multiply
    661.20x = 990 × 372.24
  4. Step 4: Simplify right side
    661.20x = 368,517.60
  5. Step 5: Solve for x
    x = 368,517.60/661.20
  6. Step 6: Final answer
    x = 557.35

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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.