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Finding the Fourth Proportional to 640.20, 960.75 and 478.20

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Solution

The fourth proportional to 640.20, 960.75 and 478.20 is: 717.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.20 : 960.75 = 478.20 : x
  2. Step 2: Convert to fraction form
    640.20/960.75 = 478.20/x
  3. Step 3: Cross multiply
    640.20x = 960.75 × 478.20
  4. Step 4: Simplify right side
    640.20x = 459,430.65
  5. Step 5: Solve for x
    x = 459,430.65/640.20
  6. Step 6: Final answer
    x = 717.64

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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.