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Finding the Fourth Proportional to 728.80, 1,090.80 and 512.80

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Solution

The fourth proportional to 728.80, 1,090.80 and 512.80 is: 767.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    728.80 : 1,090.80 = 512.80 : x
  2. Step 2: Convert to fraction form
    728.80/1,090.80 = 512.80/x
  3. Step 3: Cross multiply
    728.80x = 1,090.80 × 512.80
  4. Step 4: Simplify right side
    728.80x = 559,362.24
  5. Step 5: Solve for x
    x = 559,362.24/728.80
  6. Step 6: Final answer
    x = 767.51

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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.