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Finding the Fourth Proportional to 1,289.70, 1,933.91 and 919.30

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Solution

The fourth proportional to 1,289.70, 1,933.91 and 919.30 is: 1,378.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,289.70 : 1,933.91 = 919.30 : x
  2. Step 2: Convert to fraction form
    1,289.70/1,933.91 = 919.30/x
  3. Step 3: Cross multiply
    1,289.70x = 1,933.91 × 919.30
  4. Step 4: Simplify right side
    1,289.70x = 1,777,838.87
  5. Step 5: Solve for x
    x = 1,777,838.87/1,289.70
  6. Step 6: Final answer
    x = 1,378.50

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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.