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Finding the Fourth Proportional to 915.06, 1,261.81 and 681.78

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Solution

The fourth proportional to 915.06, 1,261.81 and 681.78 is: 940.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    915.06 : 1,261.81 = 681.78 : x
  2. Step 2: Convert to fraction form
    915.06/1,261.81 = 681.78/x
  3. Step 3: Cross multiply
    915.06x = 1,261.81 × 681.78
  4. Step 4: Simplify right side
    915.06x = 860,276.82
  5. Step 5: Solve for x
    x = 860,276.82/915.06
  6. Step 6: Final answer
    x = 940.13

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.