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Finding the Fourth Proportional to 1,138.67, 1,571.40 and 807.20

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Solution

The fourth proportional to 1,138.67, 1,571.40 and 807.20 is: 1,113.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,138.67 : 1,571.40 = 807.20 : x
  2. Step 2: Convert to fraction form
    1,138.67/1,571.40 = 807.20/x
  3. Step 3: Cross multiply
    1,138.67x = 1,571.40 × 807.20
  4. Step 4: Simplify right side
    1,138.67x = 1,268,434.08
  5. Step 5: Solve for x
    x = 1,268,434.08/1,138.67
  6. Step 6: Final answer
    x = 1,113.96

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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.