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Finding the Fourth Proportional to 1,289, 1,778.62 and 765.03

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Solution

The fourth proportional to 1,289, 1,778.62 and 765.03 is: 1,055.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,289 : 1,778.62 = 765.03 : x
  2. Step 2: Convert to fraction form
    1,289/1,778.62 = 765.03/x
  3. Step 3: Cross multiply
    1,289x = 1,778.62 × 765.03
  4. Step 4: Simplify right side
    1,289x = 1,360,697.66
  5. Step 5: Solve for x
    x = 1,360,697.66/1,289
  6. Step 6: Final answer
    x = 1,055.62

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.