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Finding the Fourth Proportional to 720.11, 1,079.55 and 287.57

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Solution

The fourth proportional to 720.11, 1,079.55 and 287.57 is: 431.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.11 : 1,079.55 = 287.57 : x
  2. Step 2: Convert to fraction form
    720.11/1,079.55 = 287.57/x
  3. Step 3: Cross multiply
    720.11x = 1,079.55 × 287.57
  4. Step 4: Simplify right side
    720.11x = 310,446.19
  5. Step 5: Solve for x
    x = 310,446.19/720.11
  6. Step 6: Final answer
    x = 431.11

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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.