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Finding the Fourth Proportional to 873.70, 1,311.47 and 642.85

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Solution

The fourth proportional to 873.70, 1,311.47 and 642.85 is: 964.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    873.70 : 1,311.47 = 642.85 : x
  2. Step 2: Convert to fraction form
    873.70/1,311.47 = 642.85/x
  3. Step 3: Cross multiply
    873.70x = 1,311.47 × 642.85
  4. Step 4: Simplify right side
    873.70x = 843,078.49
  5. Step 5: Solve for x
    x = 843,078.49/873.70
  6. Step 6: Final answer
    x = 964.95

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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.