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Finding the Fourth Proportional to 86.76, 119.78 and 65

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Solution

The fourth proportional to 86.76, 119.78 and 65 is: 89.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.76 : 119.78 = 65 : x
  2. Step 2: Convert to fraction form
    86.76/119.78 = 65/x
  3. Step 3: Cross multiply
    86.76x = 119.78 × 65
  4. Step 4: Simplify right side
    86.76x = 7,785.70
  5. Step 5: Solve for x
    x = 7,785.70/86.76
  6. Step 6: Final answer
    x = 89.74

Related Problems

Find fourth proportional to 43.38, 59.89 and 32.50
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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.