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Finding the Fourth Proportional to 1,139.67, 1,572.78 and 808.20

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Solution

The fourth proportional to 1,139.67, 1,572.78 and 808.20 is: 1,115.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,139.67 : 1,572.78 = 808.20 : x
  2. Step 2: Convert to fraction form
    1,139.67/1,572.78 = 808.20/x
  3. Step 3: Cross multiply
    1,139.67x = 1,572.78 × 808.20
  4. Step 4: Simplify right side
    1,139.67x = 1,271,120.80
  5. Step 5: Solve for x
    x = 1,271,120.80/1,139.67
  6. Step 6: Final answer
    x = 1,115.34

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.