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Finding the Fourth Proportional to 855.12, 1,279.32 and 611.76

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Solution

The fourth proportional to 855.12, 1,279.32 and 611.76 is: 915.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    855.12 : 1,279.32 = 611.76 : x
  2. Step 2: Convert to fraction form
    855.12/1,279.32 = 611.76/x
  3. Step 3: Cross multiply
    855.12x = 1,279.32 × 611.76
  4. Step 4: Simplify right side
    855.12x = 782,636.80
  5. Step 5: Solve for x
    x = 782,636.80/855.12
  6. Step 6: Final answer
    x = 915.24

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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.