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Finding the Fourth Proportional to 1,820, 2,729.72 and 521.20

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Solution

The fourth proportional to 1,820, 2,729.72 and 521.20 is: 781.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,820 : 2,729.72 = 521.20 : x
  2. Step 2: Convert to fraction form
    1,820/2,729.72 = 521.20/x
  3. Step 3: Cross multiply
    1,820x = 2,729.72 × 521.20
  4. Step 4: Simplify right side
    1,820x = 1,422,730.06
  5. Step 5: Solve for x
    x = 1,422,730.06/1,820
  6. Step 6: Final answer
    x = 781.72

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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.