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Finding the Fourth Proportional to 1,218.54, 1,826 and 639.66

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Solution

The fourth proportional to 1,218.54, 1,826 and 639.66 is: 958.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,218.54 : 1,826 = 639.66 : x
  2. Step 2: Convert to fraction form
    1,218.54/1,826 = 639.66/x
  3. Step 3: Cross multiply
    1,218.54x = 1,826 × 639.66
  4. Step 4: Simplify right side
    1,218.54x = 1,168,019.16
  5. Step 5: Solve for x
    x = 1,168,019.16/1,218.54
  6. Step 6: Final answer
    x = 958.54

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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.