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Finding the Fourth Proportional to 1,981.75, 2,972.80 and 520.91

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Solution

The fourth proportional to 1,981.75, 2,972.80 and 520.91 is: 781.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,981.75 : 2,972.80 = 520.91 : x
  2. Step 2: Convert to fraction form
    1,981.75/2,972.80 = 520.91/x
  3. Step 3: Cross multiply
    1,981.75x = 2,972.80 × 520.91
  4. Step 4: Simplify right side
    1,981.75x = 1,548,561.25
  5. Step 5: Solve for x
    x = 1,548,561.25/1,981.75
  6. Step 6: Final answer
    x = 781.41

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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.