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Finding the Fourth Proportional to 860.48, 1,291.40 and 312.82

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Solution

The fourth proportional to 860.48, 1,291.40 and 312.82 is: 469.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.48 : 1,291.40 = 312.82 : x
  2. Step 2: Convert to fraction form
    860.48/1,291.40 = 312.82/x
  3. Step 3: Cross multiply
    860.48x = 1,291.40 × 312.82
  4. Step 4: Simplify right side
    860.48x = 403,975.75
  5. Step 5: Solve for x
    x = 403,975.75/860.48
  6. Step 6: Final answer
    x = 469.48

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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.