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Finding the Fourth Proportional to 1,138.78, 1,571.50 and 666.66

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Solution

The fourth proportional to 1,138.78, 1,571.50 and 666.66 is: 919.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,138.78 : 1,571.50 = 666.66 : x
  2. Step 2: Convert to fraction form
    1,138.78/1,571.50 = 666.66/x
  3. Step 3: Cross multiply
    1,138.78x = 1,571.50 × 666.66
  4. Step 4: Simplify right side
    1,138.78x = 1,047,656.19
  5. Step 5: Solve for x
    x = 1,047,656.19/1,138.78
  6. Step 6: Final answer
    x = 919.98

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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.