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Finding the Fourth Proportional to 820.16, 1,228.64 and 386.72

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Solution

The fourth proportional to 820.16, 1,228.64 and 386.72 is: 579.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.16 : 1,228.64 = 386.72 : x
  2. Step 2: Convert to fraction form
    820.16/1,228.64 = 386.72/x
  3. Step 3: Cross multiply
    820.16x = 1,228.64 × 386.72
  4. Step 4: Simplify right side
    820.16x = 475,139.66
  5. Step 5: Solve for x
    x = 475,139.66/820.16
  6. Step 6: Final answer
    x = 579.33

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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.