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Finding the Fourth Proportional to 1,278.42, 1,917.82 and 629.20

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Solution

The fourth proportional to 1,278.42, 1,917.82 and 629.20 is: 943.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,278.42 : 1,917.82 = 629.20 : x
  2. Step 2: Convert to fraction form
    1,278.42/1,917.82 = 629.20/x
  3. Step 3: Cross multiply
    1,278.42x = 1,917.82 × 629.20
  4. Step 4: Simplify right side
    1,278.42x = 1,206,692.34
  5. Step 5: Solve for x
    x = 1,206,692.34/1,278.42
  6. Step 6: Final answer
    x = 943.89

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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.