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Finding the Fourth Proportional to 928.11, 1,390.72 and 618.81

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Solution

The fourth proportional to 928.11, 1,390.72 and 618.81 is: 927.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    928.11 : 1,390.72 = 618.81 : x
  2. Step 2: Convert to fraction form
    928.11/1,390.72 = 618.81/x
  3. Step 3: Cross multiply
    928.11x = 1,390.72 × 618.81
  4. Step 4: Simplify right side
    928.11x = 860,597.58
  5. Step 5: Solve for x
    x = 860,597.58/928.11
  6. Step 6: Final answer
    x = 927.26

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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.