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Finding the Fourth Proportional to 912.70, 1,369.05 and 758.80

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Solution

The fourth proportional to 912.70, 1,369.05 and 758.80 is: 1,138.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    912.70 : 1,369.05 = 758.80 : x
  2. Step 2: Convert to fraction form
    912.70/1,369.05 = 758.80/x
  3. Step 3: Cross multiply
    912.70x = 1,369.05 × 758.80
  4. Step 4: Simplify right side
    912.70x = 1,038,835.14
  5. Step 5: Solve for x
    x = 1,038,835.14/912.70
  6. Step 6: Final answer
    x = 1,138.20

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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.