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Finding the Fourth Proportional to 1,390.94, 2,086.82 and 805.80

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Solution

The fourth proportional to 1,390.94, 2,086.82 and 805.80 is: 1,208.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,390.94 : 2,086.82 = 805.80 : x
  2. Step 2: Convert to fraction form
    1,390.94/2,086.82 = 805.80/x
  3. Step 3: Cross multiply
    1,390.94x = 2,086.82 × 805.80
  4. Step 4: Simplify right side
    1,390.94x = 1,681,566.79
  5. Step 5: Solve for x
    x = 1,681,566.79/1,390.94
  6. Step 6: Final answer
    x = 1,208.94

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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.