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Finding the Fourth Proportional to 642.80, 964.37 and 209.95

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Solution

The fourth proportional to 642.80, 964.37 and 209.95 is: 314.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.80 : 964.37 = 209.95 : x
  2. Step 2: Convert to fraction form
    642.80/964.37 = 209.95/x
  3. Step 3: Cross multiply
    642.80x = 964.37 × 209.95
  4. Step 4: Simplify right side
    642.80x = 202,473.02
  5. Step 5: Solve for x
    x = 202,473.02/642.80
  6. Step 6: Final answer
    x = 314.99

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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.