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Finding the Fourth Proportional to 720.65, 1,080.90 and 411.53

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Solution

The fourth proportional to 720.65, 1,080.90 and 411.53 is: 617.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.65 : 1,080.90 = 411.53 : x
  2. Step 2: Convert to fraction form
    720.65/1,080.90 = 411.53/x
  3. Step 3: Cross multiply
    720.65x = 1,080.90 × 411.53
  4. Step 4: Simplify right side
    720.65x = 444,817.37
  5. Step 5: Solve for x
    x = 444,817.37/720.65
  6. Step 6: Final answer
    x = 617.25

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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.