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Finding the Fourth Proportional to 728.81, 1,004.68 and 640.65

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Solution

The fourth proportional to 728.81, 1,004.68 and 640.65 is: 883.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    728.81 : 1,004.68 = 640.65 : x
  2. Step 2: Convert to fraction form
    728.81/1,004.68 = 640.65/x
  3. Step 3: Cross multiply
    728.81x = 1,004.68 × 640.65
  4. Step 4: Simplify right side
    728.81x = 643,648.24
  5. Step 5: Solve for x
    x = 643,648.24/728.81
  6. Step 6: Final answer
    x = 883.15

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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.