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Finding the Fourth Proportional to 1,005.12, 1,505.92 and 640.32

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Solution

The fourth proportional to 1,005.12, 1,505.92 and 640.32 is: 959.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,005.12 : 1,505.92 = 640.32 : x
  2. Step 2: Convert to fraction form
    1,005.12/1,505.92 = 640.32/x
  3. Step 3: Cross multiply
    1,005.12x = 1,505.92 × 640.32
  4. Step 4: Simplify right side
    1,005.12x = 964,270.69
  5. Step 5: Solve for x
    x = 964,270.69/1,005.12
  6. Step 6: Final answer
    x = 959.36

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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.