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Finding the Fourth Proportional to 1,138.86, 1,707.47 and 919.76

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Solution

The fourth proportional to 1,138.86, 1,707.47 and 919.76 is: 1,378.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,138.86 : 1,707.47 = 919.76 : x
  2. Step 2: Convert to fraction form
    1,138.86/1,707.47 = 919.76/x
  3. Step 3: Cross multiply
    1,138.86x = 1,707.47 × 919.76
  4. Step 4: Simplify right side
    1,138.86x = 1,570,449.47
  5. Step 5: Solve for x
    x = 1,570,449.47/1,138.86
  6. Step 6: Final answer
    x = 1,378.97

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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.