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Finding the Fourth Proportional to 78.98, 109.08 and 78.32

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Solution

The fourth proportional to 78.98, 109.08 and 78.32 is: 108.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.98 : 109.08 = 78.32 : x
  2. Step 2: Convert to fraction form
    78.98/109.08 = 78.32/x
  3. Step 3: Cross multiply
    78.98x = 109.08 × 78.32
  4. Step 4: Simplify right side
    78.98x = 8,543.15
  5. Step 5: Solve for x
    x = 8,543.15/78.98
  6. Step 6: Final answer
    x = 108.17

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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.