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Finding the Fourth Proportional to 486.88, 728.80 and 258.40

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Solution

The fourth proportional to 486.88, 728.80 and 258.40 is: 386.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    486.88 : 728.80 = 258.40 : x
  2. Step 2: Convert to fraction form
    486.88/728.80 = 258.40/x
  3. Step 3: Cross multiply
    486.88x = 728.80 × 258.40
  4. Step 4: Simplify right side
    486.88x = 188,321.92
  5. Step 5: Solve for x
    x = 188,321.92/486.88
  6. Step 6: Final answer
    x = 386.79

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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.