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Finding the Fourth Proportional to 728.93, 1,091.76 and 420.05

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Solution

The fourth proportional to 728.93, 1,091.76 and 420.05 is: 629.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    728.93 : 1,091.76 = 420.05 : x
  2. Step 2: Convert to fraction form
    728.93/1,091.76 = 420.05/x
  3. Step 3: Cross multiply
    728.93x = 1,091.76 × 420.05
  4. Step 4: Simplify right side
    728.93x = 458,591.69
  5. Step 5: Solve for x
    x = 458,591.69/728.93
  6. Step 6: Final answer
    x = 629.13

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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.