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Finding the Fourth Proportional to 486.18, 728.58 and 428.28

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Solution

The fourth proportional to 486.18, 728.58 and 428.28 is: 641.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    486.18 : 728.58 = 428.28 : x
  2. Step 2: Convert to fraction form
    486.18/728.58 = 428.28/x
  3. Step 3: Cross multiply
    486.18x = 728.58 × 428.28
  4. Step 4: Simplify right side
    486.18x = 312,036.24
  5. Step 5: Solve for x
    x = 312,036.24/486.18
  6. Step 6: Final answer
    x = 641.81

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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.