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Finding the Fourth Proportional to 78, 117.62 and 67.98

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Solution

The fourth proportional to 78, 117.62 and 67.98 is: 102.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    78 : 117.62 = 67.98 : x
  2. Step 2: Convert to fraction form
    78/117.62 = 67.98/x
  3. Step 3: Cross multiply
    78x = 117.62 × 67.98
  4. Step 4: Simplify right side
    78x = 7,995.81
  5. Step 5: Solve for x
    x = 7,995.81/78
  6. Step 6: Final answer
    x = 102.51

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.