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Finding the Fourth Proportional to 66.63, 99.95 and 53.21

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Solution

The fourth proportional to 66.63, 99.95 and 53.21 is: 79.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.63 : 99.95 = 53.21 : x
  2. Step 2: Convert to fraction form
    66.63/99.95 = 53.21/x
  3. Step 3: Cross multiply
    66.63x = 99.95 × 53.21
  4. Step 4: Simplify right side
    66.63x = 5,317.57
  5. Step 5: Solve for x
    x = 5,317.57/66.63
  6. Step 6: Final answer
    x = 79.81

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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.