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Finding the Fourth Proportional to 860.84, 1,291 and 312.92

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Solution

The fourth proportional to 860.84, 1,291 and 312.92 is: 469.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.84 : 1,291 = 312.92 : x
  2. Step 2: Convert to fraction form
    860.84/1,291 = 312.92/x
  3. Step 3: Cross multiply
    860.84x = 1,291 × 312.92
  4. Step 4: Simplify right side
    860.84x = 403,979.72
  5. Step 5: Solve for x
    x = 403,979.72/860.84
  6. Step 6: Final answer
    x = 469.29

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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.