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Finding the Fourth Proportional to 66.15, 90.84 and 55.20

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Solution

The fourth proportional to 66.15, 90.84 and 55.20 is: 75.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.15 : 90.84 = 55.20 : x
  2. Step 2: Convert to fraction form
    66.15/90.84 = 55.20/x
  3. Step 3: Cross multiply
    66.15x = 90.84 × 55.20
  4. Step 4: Simplify right side
    66.15x = 5,014.37
  5. Step 5: Solve for x
    x = 5,014.37/66.15
  6. Step 6: Final answer
    x = 75.80

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.