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Finding the Fourth Proportional to 1,938.29, 2,907.89 and 639.75

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Solution

The fourth proportional to 1,938.29, 2,907.89 and 639.75 is: 959.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,938.29 : 2,907.89 = 639.75 : x
  2. Step 2: Convert to fraction form
    1,938.29/2,907.89 = 639.75/x
  3. Step 3: Cross multiply
    1,938.29x = 2,907.89 × 639.75
  4. Step 4: Simplify right side
    1,938.29x = 1,860,319.43
  5. Step 5: Solve for x
    x = 1,860,319.43/1,938.29
  6. Step 6: Final answer
    x = 959.78

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1.5x scale

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.