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Finding the Fourth Proportional to 78.88, 117.83 and 66.72

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Solution

The fourth proportional to 78.88, 117.83 and 66.72 is: 99.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.88 : 117.83 = 66.72 : x
  2. Step 2: Convert to fraction form
    78.88/117.83 = 66.72/x
  3. Step 3: Cross multiply
    78.88x = 117.83 × 66.72
  4. Step 4: Simplify right side
    78.88x = 7,861.62
  5. Step 5: Solve for x
    x = 7,861.62/78.88
  6. Step 6: Final answer
    x = 99.67

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.