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Finding the Fourth Proportional to 720.42, 1,080.57 and 257.94

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Solution

The fourth proportional to 720.42, 1,080.57 and 257.94 is: 386.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.42 : 1,080.57 = 257.94 : x
  2. Step 2: Convert to fraction form
    720.42/1,080.57 = 257.94/x
  3. Step 3: Cross multiply
    720.42x = 1,080.57 × 257.94
  4. Step 4: Simplify right side
    720.42x = 278,722.23
  5. Step 5: Solve for x
    x = 278,722.23/720.42
  6. Step 6: Final answer
    x = 386.89

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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.