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Finding the Fourth Proportional to 642.90, 964.44 and 209.92

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Solution

The fourth proportional to 642.90, 964.44 and 209.92 is: 314.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.90 : 964.44 = 209.92 : x
  2. Step 2: Convert to fraction form
    642.90/964.44 = 209.92/x
  3. Step 3: Cross multiply
    642.90x = 964.44 × 209.92
  4. Step 4: Simplify right side
    642.90x = 202,455.24
  5. Step 5: Solve for x
    x = 202,455.24/642.90
  6. Step 6: Final answer
    x = 314.91

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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.