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Finding the Fourth Proportional to 117.20, 161.72 and 65.45

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Solution

The fourth proportional to 117.20, 161.72 and 65.45 is: 90.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    117.20 : 161.72 = 65.45 : x
  2. Step 2: Convert to fraction form
    117.20/161.72 = 65.45/x
  3. Step 3: Cross multiply
    117.20x = 161.72 × 65.45
  4. Step 4: Simplify right side
    117.20x = 10,583.44
  5. Step 5: Solve for x
    x = 10,583.44/117.20
  6. Step 6: Final answer
    x = 90.31

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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.