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Finding the Fourth Proportional to 728.64, 1,005.21 and 448.78

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Solution

The fourth proportional to 728.64, 1,005.21 and 448.78 is: 619.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    728.64 : 1,005.21 = 448.78 : x
  2. Step 2: Convert to fraction form
    728.64/1,005.21 = 448.78/x
  3. Step 3: Cross multiply
    728.64x = 1,005.21 × 448.78
  4. Step 4: Simplify right side
    728.64x = 451,118.14
  5. Step 5: Solve for x
    x = 451,118.14/728.64
  6. Step 6: Final answer
    x = 619.12

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.