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Finding the Fourth Proportional to 86.76, 129.80 and 66.51

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Solution

The fourth proportional to 86.76, 129.80 and 66.51 is: 99.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.76 : 129.80 = 66.51 : x
  2. Step 2: Convert to fraction form
    86.76/129.80 = 66.51/x
  3. Step 3: Cross multiply
    86.76x = 129.80 × 66.51
  4. Step 4: Simplify right side
    86.76x = 8,633.16
  5. Step 5: Solve for x
    x = 8,633.16/86.76
  6. Step 6: Final answer
    x = 99.51

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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.