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Finding the Fourth Proportional to 805.51, 1,208.39 and 257.75

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Solution

The fourth proportional to 805.51, 1,208.39 and 257.75 is: 386.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    805.51 : 1,208.39 = 257.75 : x
  2. Step 2: Convert to fraction form
    805.51/1,208.39 = 257.75/x
  3. Step 3: Cross multiply
    805.51x = 1,208.39 × 257.75
  4. Step 4: Simplify right side
    805.51x = 311,459.72
  5. Step 5: Solve for x
    x = 311,459.72/805.51
  6. Step 6: Final answer
    x = 386.66

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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.