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Finding the Fourth Proportional to 860.58, 1,288.74 and 821.10

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Solution

The fourth proportional to 860.58, 1,288.74 and 821.10 is: 1,229.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.58 : 1,288.74 = 821.10 : x
  2. Step 2: Convert to fraction form
    860.58/1,288.74 = 821.10/x
  3. Step 3: Cross multiply
    860.58x = 1,288.74 × 821.10
  4. Step 4: Simplify right side
    860.58x = 1,058,184.41
  5. Step 5: Solve for x
    x = 1,058,184.41/860.58
  6. Step 6: Final answer
    x = 1,229.62

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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.