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Finding the Fourth Proportional to 88.16, 121.62 and 78.42

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Solution

The fourth proportional to 88.16, 121.62 and 78.42 is: 108.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    88.16 : 121.62 = 78.42 : x
  2. Step 2: Convert to fraction form
    88.16/121.62 = 78.42/x
  3. Step 3: Cross multiply
    88.16x = 121.62 × 78.42
  4. Step 4: Simplify right side
    88.16x = 9,537.44
  5. Step 5: Solve for x
    x = 9,537.44/88.16
  6. Step 6: Final answer
    x = 108.18

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.