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Finding the Fourth Proportional to 117.16, 161.90 and 87.78

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Solution

The fourth proportional to 117.16, 161.90 and 87.78 is: 121.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    117.16 : 161.90 = 87.78 : x
  2. Step 2: Convert to fraction form
    117.16/161.90 = 87.78/x
  3. Step 3: Cross multiply
    117.16x = 161.90 × 87.78
  4. Step 4: Simplify right side
    117.16x = 14,211.58
  5. Step 5: Solve for x
    x = 14,211.58/117.16
  6. Step 6: Final answer
    x = 121.30

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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.