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Finding the Fourth Proportional to 218.85, 328.35 and 64.78

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Solution

The fourth proportional to 218.85, 328.35 and 64.78 is: 97.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    218.85 : 328.35 = 64.78 : x
  2. Step 2: Convert to fraction form
    218.85/328.35 = 64.78/x
  3. Step 3: Cross multiply
    218.85x = 328.35 × 64.78
  4. Step 4: Simplify right side
    218.85x = 21,270.68
  5. Step 5: Solve for x
    x = 21,270.68/218.85
  6. Step 6: Final answer
    x = 97.19

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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.