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Finding the Fourth Proportional to 1,205.40, 1,808.10 and 1,111.80

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Solution

The fourth proportional to 1,205.40, 1,808.10 and 1,111.80 is: 1,667.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,205.40 : 1,808.10 = 1,111.80 : x
  2. Step 2: Convert to fraction form
    1,205.40/1,808.10 = 1,111.80/x
  3. Step 3: Cross multiply
    1,205.40x = 1,808.10 × 1,111.80
  4. Step 4: Simplify right side
    1,205.40x = 2,010,245.58
  5. Step 5: Solve for x
    x = 2,010,245.58/1,205.40
  6. Step 6: Final answer
    x = 1,667.70

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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.