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Finding the Fourth Proportional to 1,390.80, 2,086.32 and 453.80

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Solution

The fourth proportional to 1,390.80, 2,086.32 and 453.80 is: 680.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,390.80 : 2,086.32 = 453.80 : x
  2. Step 2: Convert to fraction form
    1,390.80/2,086.32 = 453.80/x
  3. Step 3: Cross multiply
    1,390.80x = 2,086.32 × 453.80
  4. Step 4: Simplify right side
    1,390.80x = 946,778.93
  5. Step 5: Solve for x
    x = 946,778.93/1,390.80
  6. Step 6: Final answer
    x = 680.74

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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.