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Finding the Fourth Proportional to 1,308.78, 1,963.04 and 820.35

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Solution

The fourth proportional to 1,308.78, 1,963.04 and 820.35 is: 1,230.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,308.78 : 1,963.04 = 820.35 : x
  2. Step 2: Convert to fraction form
    1,308.78/1,963.04 = 820.35/x
  3. Step 3: Cross multiply
    1,308.78x = 1,963.04 × 820.35
  4. Step 4: Simplify right side
    1,308.78x = 1,610,375.76
  5. Step 5: Solve for x
    x = 1,610,375.76/1,308.78
  6. Step 6: Final answer
    x = 1,230.44

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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.