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Finding the Fourth Proportional to 812.32, 1,219.28 and 427.84

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Solution

The fourth proportional to 812.32, 1,219.28 and 427.84 is: 642.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.32 : 1,219.28 = 427.84 : x
  2. Step 2: Convert to fraction form
    812.32/1,219.28 = 427.84/x
  3. Step 3: Cross multiply
    812.32x = 1,219.28 × 427.84
  4. Step 4: Simplify right side
    812.32x = 521,656.76
  5. Step 5: Solve for x
    x = 521,656.76/812.32
  6. Step 6: Final answer
    x = 642.18

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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.