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Finding the Fourth Proportional to 78.77, 118.26 and 72.70

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Solution

The fourth proportional to 78.77, 118.26 and 72.70 is: 109.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.77 : 118.26 = 72.70 : x
  2. Step 2: Convert to fraction form
    78.77/118.26 = 72.70/x
  3. Step 3: Cross multiply
    78.77x = 118.26 × 72.70
  4. Step 4: Simplify right side
    78.77x = 8,597.21
  5. Step 5: Solve for x
    x = 8,597.21/78.77
  6. Step 6: Final answer
    x = 109.14

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.