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Finding the Fourth Proportional to 728.65, 1,091.93 and 420.58

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Solution

The fourth proportional to 728.65, 1,091.93 and 420.58 is: 630.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    728.65 : 1,091.93 = 420.58 : x
  2. Step 2: Convert to fraction form
    728.65/1,091.93 = 420.58/x
  3. Step 3: Cross multiply
    728.65x = 1,091.93 × 420.58
  4. Step 4: Simplify right side
    728.65x = 459,242.24
  5. Step 5: Solve for x
    x = 459,242.24/728.65
  6. Step 6: Final answer
    x = 630.27

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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.