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Finding the Fourth Proportional to 321.76, 482.64 and 78.28

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Solution

The fourth proportional to 321.76, 482.64 and 78.28 is: 117.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    321.76 : 482.64 = 78.28 : x
  2. Step 2: Convert to fraction form
    321.76/482.64 = 78.28/x
  3. Step 3: Cross multiply
    321.76x = 482.64 × 78.28
  4. Step 4: Simplify right side
    321.76x = 37,782.55
  5. Step 5: Solve for x
    x = 37,782.55/321.76
  6. Step 6: Final answer
    x = 117.42

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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.