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Finding the Fourth Proportional to 860.55, 1,290.82 and 312.73

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Solution

The fourth proportional to 860.55, 1,290.82 and 312.73 is: 469.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.55 : 1,290.82 = 312.73 : x
  2. Step 2: Convert to fraction form
    860.55/1,290.82 = 312.73/x
  3. Step 3: Cross multiply
    860.55x = 1,290.82 × 312.73
  4. Step 4: Simplify right side
    860.55x = 403,670.12
  5. Step 5: Solve for x
    x = 403,670.12/860.55
  6. Step 6: Final answer
    x = 469.09

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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.