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Finding the Fourth Proportional to 1,289.86, 1,780 and 700.38

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Solution

The fourth proportional to 1,289.86, 1,780 and 700.38 is: 966.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,289.86 : 1,780 = 700.38 : x
  2. Step 2: Convert to fraction form
    1,289.86/1,780 = 700.38/x
  3. Step 3: Cross multiply
    1,289.86x = 1,780 × 700.38
  4. Step 4: Simplify right side
    1,289.86x = 1,246,676.40
  5. Step 5: Solve for x
    x = 1,246,676.40/1,289.86
  6. Step 6: Final answer
    x = 966.52

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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.