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Finding the Fourth Proportional to 720.09, 1,079.75 and 257.81

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Solution

The fourth proportional to 720.09, 1,079.75 and 257.81 is: 386.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.09 : 1,079.75 = 257.81 : x
  2. Step 2: Convert to fraction form
    720.09/1,079.75 = 257.81/x
  3. Step 3: Cross multiply
    720.09x = 1,079.75 × 257.81
  4. Step 4: Simplify right side
    720.09x = 278,363.66
  5. Step 5: Solve for x
    x = 278,363.66/720.09
  6. Step 6: Final answer
    x = 386.57

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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.