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Finding the Fourth Proportional to 117.32, 161.86 and 78.51

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Solution

The fourth proportional to 117.32, 161.86 and 78.51 is: 108.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    117.32 : 161.86 = 78.51 : x
  2. Step 2: Convert to fraction form
    117.32/161.86 = 78.51/x
  3. Step 3: Cross multiply
    117.32x = 161.86 × 78.51
  4. Step 4: Simplify right side
    117.32x = 12,707.63
  5. Step 5: Solve for x
    x = 12,707.63/117.32
  6. Step 6: Final answer
    x = 108.32

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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.