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Finding the Fourth Proportional to 485.28, 728 and 143.28

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Solution

The fourth proportional to 485.28, 728 and 143.28 is: 214.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.28 : 728 = 143.28 : x
  2. Step 2: Convert to fraction form
    485.28/728 = 143.28/x
  3. Step 3: Cross multiply
    485.28x = 728 × 143.28
  4. Step 4: Simplify right side
    485.28x = 104,307.84
  5. Step 5: Solve for x
    x = 104,307.84/485.28
  6. Step 6: Final answer
    x = 214.94

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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.