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Finding the Fourth Proportional to 1,211.32, 1,815.31 and 691.57

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Solution

The fourth proportional to 1,211.32, 1,815.31 and 691.57 is: 1,036.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,211.32 : 1,815.31 = 691.57 : x
  2. Step 2: Convert to fraction form
    1,211.32/1,815.31 = 691.57/x
  3. Step 3: Cross multiply
    1,211.32x = 1,815.31 × 691.57
  4. Step 4: Simplify right side
    1,211.32x = 1,255,413.94
  5. Step 5: Solve for x
    x = 1,255,413.94/1,211.32
  6. Step 6: Final answer
    x = 1,036.40

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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.