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Finding the Fourth Proportional to 860.78, 1,291.14 and 422.36

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Solution

The fourth proportional to 860.78, 1,291.14 and 422.36 is: 633.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.78 : 1,291.14 = 422.36 : x
  2. Step 2: Convert to fraction form
    860.78/1,291.14 = 422.36/x
  3. Step 3: Cross multiply
    860.78x = 1,291.14 × 422.36
  4. Step 4: Simplify right side
    860.78x = 545,325.89
  5. Step 5: Solve for x
    x = 545,325.89/860.78
  6. Step 6: Final answer
    x = 633.53

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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.