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Finding the Fourth Proportional to 956.70, 1,321.16 and 642.21

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Solution

The fourth proportional to 956.70, 1,321.16 and 642.21 is: 886.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    956.70 : 1,321.16 = 642.21 : x
  2. Step 2: Convert to fraction form
    956.70/1,321.16 = 642.21/x
  3. Step 3: Cross multiply
    956.70x = 1,321.16 × 642.21
  4. Step 4: Simplify right side
    956.70x = 848,458.95
  5. Step 5: Solve for x
    x = 848,458.95/956.70
  6. Step 6: Final answer
    x = 886.86

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.