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Finding the Fourth Proportional to 640.65, 961.18 and 380.95

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Solution

The fourth proportional to 640.65, 961.18 and 380.95 is: 571.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.65 : 961.18 = 380.95 : x
  2. Step 2: Convert to fraction form
    640.65/961.18 = 380.95/x
  3. Step 3: Cross multiply
    640.65x = 961.18 × 380.95
  4. Step 4: Simplify right side
    640.65x = 366,158.17
  5. Step 5: Solve for x
    x = 366,158.17/640.65
  6. Step 6: Final answer
    x = 571.54

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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.