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Finding the Fourth Proportional to 1,938.24, 2,908.08 and 639.72

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Solution

The fourth proportional to 1,938.24, 2,908.08 and 639.72 is: 959.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,938.24 : 2,908.08 = 639.72 : x
  2. Step 2: Convert to fraction form
    1,938.24/2,908.08 = 639.72/x
  3. Step 3: Cross multiply
    1,938.24x = 2,908.08 × 639.72
  4. Step 4: Simplify right side
    1,938.24x = 1,860,356.94
  5. Step 5: Solve for x
    x = 1,860,356.94/1,938.24
  6. Step 6: Final answer
    x = 959.82

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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.