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Finding the Fourth Proportional to 82.10, 123 and 53.21

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Solution

The fourth proportional to 82.10, 123 and 53.21 is: 79.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.10 : 123 = 53.21 : x
  2. Step 2: Convert to fraction form
    82.10/123 = 53.21/x
  3. Step 3: Cross multiply
    82.10x = 123 × 53.21
  4. Step 4: Simplify right side
    82.10x = 6,544.83
  5. Step 5: Solve for x
    x = 6,544.83/82.10
  6. Step 6: Final answer
    x = 79.72

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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.