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Finding the Fourth Proportional to 1,278.37, 1,914.47 and 728.89

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Solution

The fourth proportional to 1,278.37, 1,914.47 and 728.89 is: 1,091.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,278.37 : 1,914.47 = 728.89 : x
  2. Step 2: Convert to fraction form
    1,278.37/1,914.47 = 728.89/x
  3. Step 3: Cross multiply
    1,278.37x = 1,914.47 × 728.89
  4. Step 4: Simplify right side
    1,278.37x = 1,395,438.04
  5. Step 5: Solve for x
    x = 1,395,438.04/1,278.37
  6. Step 6: Final answer
    x = 1,091.58

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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.