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Finding the Fourth Proportional to 860.58, 1,290.61 and 312.61

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Solution

The fourth proportional to 860.58, 1,290.61 and 312.61 is: 468.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.58 : 1,290.61 = 312.61 : x
  2. Step 2: Convert to fraction form
    860.58/1,290.61 = 312.61/x
  3. Step 3: Cross multiply
    860.58x = 1,290.61 × 312.61
  4. Step 4: Simplify right side
    860.58x = 403,457.59
  5. Step 5: Solve for x
    x = 403,457.59/860.58
  6. Step 6: Final answer
    x = 468.82

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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.