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Finding the Fourth Proportional to 86.77, 130.76 and 78.22

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Solution

The fourth proportional to 86.77, 130.76 and 78.22 is: 117.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.77 : 130.76 = 78.22 : x
  2. Step 2: Convert to fraction form
    86.77/130.76 = 78.22/x
  3. Step 3: Cross multiply
    86.77x = 130.76 × 78.22
  4. Step 4: Simplify right side
    86.77x = 10,228.05
  5. Step 5: Solve for x
    x = 10,228.05/86.77
  6. Step 6: Final answer
    x = 117.88

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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.