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Finding the Fourth Proportional to 915.63, 1,380.63 and 839.09

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Solution

The fourth proportional to 915.63, 1,380.63 and 839.09 is: 1,265.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    915.63 : 1,380.63 = 839.09 : x
  2. Step 2: Convert to fraction form
    915.63/1,380.63 = 839.09/x
  3. Step 3: Cross multiply
    915.63x = 1,380.63 × 839.09
  4. Step 4: Simplify right side
    915.63x = 1,158,463.83
  5. Step 5: Solve for x
    x = 1,158,463.83/915.63
  6. Step 6: Final answer
    x = 1,265.21

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.