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Finding the Fourth Proportional to 640, 960.40 and 255.28

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Solution

The fourth proportional to 640, 960.40 and 255.28 is: 383.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    640 : 960.40 = 255.28 : x
  2. Step 2: Convert to fraction form
    640/960.40 = 255.28/x
  3. Step 3: Cross multiply
    640x = 960.40 × 255.28
  4. Step 4: Simplify right side
    640x = 245,170.91
  5. Step 5: Solve for x
    x = 245,170.91/640
  6. Step 6: Final answer
    x = 383.08

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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.