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Finding the Fourth Proportional to 1,238.90, 1,709.67 and 679.35

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Solution

The fourth proportional to 1,238.90, 1,709.67 and 679.35 is: 937.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,238.90 : 1,709.67 = 679.35 : x
  2. Step 2: Convert to fraction form
    1,238.90/1,709.67 = 679.35/x
  3. Step 3: Cross multiply
    1,238.90x = 1,709.67 × 679.35
  4. Step 4: Simplify right side
    1,238.90x = 1,161,464.31
  5. Step 5: Solve for x
    x = 1,161,464.31/1,238.90
  6. Step 6: Final answer
    x = 937.50

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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.