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Finding the Fourth Proportional to 66.55, 91.80 and 38.91

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Solution

The fourth proportional to 66.55, 91.80 and 38.91 is: 53.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.55 : 91.80 = 38.91 : x
  2. Step 2: Convert to fraction form
    66.55/91.80 = 38.91/x
  3. Step 3: Cross multiply
    66.55x = 91.80 × 38.91
  4. Step 4: Simplify right side
    66.55x = 3,571.94
  5. Step 5: Solve for x
    x = 3,571.94/66.55
  6. Step 6: Final answer
    x = 53.67

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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.