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Finding the Fourth Proportional to 1,388.14, 2,078.94 and 728.44

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Solution

The fourth proportional to 1,388.14, 2,078.94 and 728.44 is: 1,090.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,388.14 : 2,078.94 = 728.44 : x
  2. Step 2: Convert to fraction form
    1,388.14/2,078.94 = 728.44/x
  3. Step 3: Cross multiply
    1,388.14x = 2,078.94 × 728.44
  4. Step 4: Simplify right side
    1,388.14x = 1,514,383.05
  5. Step 5: Solve for x
    x = 1,514,383.05/1,388.14
  6. Step 6: Final answer
    x = 1,090.94

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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.