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Finding the Fourth Proportional to 218.40, 309.60 and 218.40

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Solution

The fourth proportional to 218.40, 309.60 and 218.40 is: 309.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    218.40 : 309.60 = 218.40 : x
  2. Step 2: Convert to fraction form
    218.40/309.60 = 218.40/x
  3. Step 3: Cross multiply
    218.40x = 309.60 × 218.40
  4. Step 4: Simplify right side
    218.40x = 67,616.64
  5. Step 5: Solve for x
    x = 67,616.64/218.40
  6. Step 6: Final answer
    x = 309.60

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Why These Related Problems?

These problems maintain the same ratio (1.42) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.