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Finding the Fourth Proportional to 1,205.80, 1,808.70 and 1,138.60

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Solution

The fourth proportional to 1,205.80, 1,808.70 and 1,138.60 is: 1,707.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,205.80 : 1,808.70 = 1,138.60 : x
  2. Step 2: Convert to fraction form
    1,205.80/1,808.70 = 1,138.60/x
  3. Step 3: Cross multiply
    1,205.80x = 1,808.70 × 1,138.60
  4. Step 4: Simplify right side
    1,205.80x = 2,059,385.82
  5. Step 5: Solve for x
    x = 2,059,385.82/1,205.80
  6. Step 6: Final answer
    x = 1,707.90

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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.