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Finding the Fourth Proportional to 1,391.40, 2,086.02 and 661.86

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Solution

The fourth proportional to 1,391.40, 2,086.02 and 661.86 is: 992.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,391.40 : 2,086.02 = 661.86 : x
  2. Step 2: Convert to fraction form
    1,391.40/2,086.02 = 661.86/x
  3. Step 3: Cross multiply
    1,391.40x = 2,086.02 × 661.86
  4. Step 4: Simplify right side
    1,391.40x = 1,380,653.20
  5. Step 5: Solve for x
    x = 1,380,653.20/1,391.40
  6. Step 6: Final answer
    x = 992.28

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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.