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Finding the Fourth Proportional to 858.43, 1,288.26 and 642.58

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Solution

The fourth proportional to 858.43, 1,288.26 and 642.58 is: 964.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.43 : 1,288.26 = 642.58 : x
  2. Step 2: Convert to fraction form
    858.43/1,288.26 = 642.58/x
  3. Step 3: Cross multiply
    858.43x = 1,288.26 × 642.58
  4. Step 4: Simplify right side
    858.43x = 827,810.11
  5. Step 5: Solve for x
    x = 827,810.11/858.43
  6. Step 6: Final answer
    x = 964.33

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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.