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Finding the Fourth Proportional to 642.50, 963.75 and 209.69

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Solution

The fourth proportional to 642.50, 963.75 and 209.69 is: 314.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.50 : 963.75 = 209.69 : x
  2. Step 2: Convert to fraction form
    642.50/963.75 = 209.69/x
  3. Step 3: Cross multiply
    642.50x = 963.75 × 209.69
  4. Step 4: Simplify right side
    642.50x = 202,088.74
  5. Step 5: Solve for x
    x = 202,088.74/642.50
  6. Step 6: Final answer
    x = 314.54

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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.