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Finding the Fourth Proportional to 860.57, 1,290.08 and 421.57

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Solution

The fourth proportional to 860.57, 1,290.08 and 421.57 is: 631.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.57 : 1,290.08 = 421.57 : x
  2. Step 2: Convert to fraction form
    860.57/1,290.08 = 421.57/x
  3. Step 3: Cross multiply
    860.57x = 1,290.08 × 421.57
  4. Step 4: Simplify right side
    860.57x = 543,850.47
  5. Step 5: Solve for x
    x = 543,850.47/860.57
  6. Step 6: Final answer
    x = 631.97

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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.