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Finding the Fourth Proportional to 860.90, 1,291.34 and 211.64

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Solution

The fourth proportional to 860.90, 1,291.34 and 211.64 is: 317.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.90 : 1,291.34 = 211.64 : x
  2. Step 2: Convert to fraction form
    860.90/1,291.34 = 211.64/x
  3. Step 3: Cross multiply
    860.90x = 1,291.34 × 211.64
  4. Step 4: Simplify right side
    860.90x = 273,299.20
  5. Step 5: Solve for x
    x = 273,299.20/860.90
  6. Step 6: Final answer
    x = 317.46

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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.