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Finding the Fourth Proportional to 1,205.78, 1,665.35 and 812.12

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Solution

The fourth proportional to 1,205.78, 1,665.35 and 812.12 is: 1,121.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,205.78 : 1,665.35 = 812.12 : x
  2. Step 2: Convert to fraction form
    1,205.78/1,665.35 = 812.12/x
  3. Step 3: Cross multiply
    1,205.78x = 1,665.35 × 812.12
  4. Step 4: Simplify right side
    1,205.78x = 1,352,464.04
  5. Step 5: Solve for x
    x = 1,352,464.04/1,205.78
  6. Step 6: Final answer
    x = 1,121.65

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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.