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Finding the Fourth Proportional to 720.84, 1,082.89 and 428.54

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Solution

The fourth proportional to 720.84, 1,082.89 and 428.54 is: 643.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.84 : 1,082.89 = 428.54 : x
  2. Step 2: Convert to fraction form
    720.84/1,082.89 = 428.54/x
  3. Step 3: Cross multiply
    720.84x = 1,082.89 × 428.54
  4. Step 4: Simplify right side
    720.84x = 464,054.12
  5. Step 5: Solve for x
    x = 464,054.12/720.84
  6. Step 6: Final answer
    x = 643.77

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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.