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Finding the Fourth Proportional to 720.47, 1,080.71 and 287.63

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Solution

The fourth proportional to 720.47, 1,080.71 and 287.63 is: 431.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.47 : 1,080.71 = 287.63 : x
  2. Step 2: Convert to fraction form
    720.47/1,080.71 = 287.63/x
  3. Step 3: Cross multiply
    720.47x = 1,080.71 × 287.63
  4. Step 4: Simplify right side
    720.47x = 310,844.62
  5. Step 5: Solve for x
    x = 310,844.62/720.47
  6. Step 6: Final answer
    x = 431.45

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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.