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Finding the Fourth Proportional to 720.37, 1,080.69 and 428.37

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Solution

The fourth proportional to 720.37, 1,080.69 and 428.37 is: 642.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.37 : 1,080.69 = 428.37 : x
  2. Step 2: Convert to fraction form
    720.37/1,080.69 = 428.37/x
  3. Step 3: Cross multiply
    720.37x = 1,080.69 × 428.37
  4. Step 4: Simplify right side
    720.37x = 462,935.18
  5. Step 5: Solve for x
    x = 462,935.18/720.37
  6. Step 6: Final answer
    x = 642.64

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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.