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Finding the Fourth Proportional to 915.36, 1,262.80 and 620.80

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Solution

The fourth proportional to 915.36, 1,262.80 and 620.80 is: 856.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    915.36 : 1,262.80 = 620.80 : x
  2. Step 2: Convert to fraction form
    915.36/1,262.80 = 620.80/x
  3. Step 3: Cross multiply
    915.36x = 1,262.80 × 620.80
  4. Step 4: Simplify right side
    915.36x = 783,946.24
  5. Step 5: Solve for x
    x = 783,946.24/915.36
  6. Step 6: Final answer
    x = 856.43

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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.