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Finding the Fourth Proportional to 661.20, 990.96 and 276

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Solution

The fourth proportional to 661.20, 990.96 and 276 is: 413.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.20 : 990.96 = 276 : x
  2. Step 2: Convert to fraction form
    661.20/990.96 = 276/x
  3. Step 3: Cross multiply
    661.20x = 990.96 × 276
  4. Step 4: Simplify right side
    661.20x = 273,504.96
  5. Step 5: Solve for x
    x = 273,504.96/661.20
  6. Step 6: Final answer
    x = 413.65

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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.