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Finding the Fourth Proportional to 53.12, 79.72 and 21.06

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Solution

The fourth proportional to 53.12, 79.72 and 21.06 is: 31.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    53.12 : 79.72 = 21.06 : x
  2. Step 2: Convert to fraction form
    53.12/79.72 = 21.06/x
  3. Step 3: Cross multiply
    53.12x = 79.72 × 21.06
  4. Step 4: Simplify right side
    53.12x = 1,678.90
  5. Step 5: Solve for x
    x = 1,678.90/53.12
  6. Step 6: Final answer
    x = 31.61

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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.