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Finding the Fourth Proportional to 992.30, 1,369.05 and 660.78

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Solution

The fourth proportional to 992.30, 1,369.05 and 660.78 is: 911.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    992.30 : 1,369.05 = 660.78 : x
  2. Step 2: Convert to fraction form
    992.30/1,369.05 = 660.78/x
  3. Step 3: Cross multiply
    992.30x = 1,369.05 × 660.78
  4. Step 4: Simplify right side
    992.30x = 904,640.86
  5. Step 5: Solve for x
    x = 904,640.86/992.30
  6. Step 6: Final answer
    x = 911.67

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.