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Finding the Fourth Proportional to 1,219.89, 1,830.35 and 781.64

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Solution

The fourth proportional to 1,219.89, 1,830.35 and 781.64 is: 1,172.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,219.89 : 1,830.35 = 781.64 : x
  2. Step 2: Convert to fraction form
    1,219.89/1,830.35 = 781.64/x
  3. Step 3: Cross multiply
    1,219.89x = 1,830.35 × 781.64
  4. Step 4: Simplify right side
    1,219.89x = 1,430,670.04
  5. Step 5: Solve for x
    x = 1,430,670.04/1,219.89
  6. Step 6: Final answer
    x = 1,172.78

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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.