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Finding the Fourth Proportional to 1,821.20, 2,729.15 and 987.55

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Solution

The fourth proportional to 1,821.20, 2,729.15 and 987.55 is: 1,479.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,821.20 : 2,729.15 = 987.55 : x
  2. Step 2: Convert to fraction form
    1,821.20/2,729.15 = 987.55/x
  3. Step 3: Cross multiply
    1,821.20x = 2,729.15 × 987.55
  4. Step 4: Simplify right side
    1,821.20x = 2,695,174.26
  5. Step 5: Solve for x
    x = 2,695,174.26/1,821.20
  6. Step 6: Final answer
    x = 1,479.89

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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.