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Finding the Fourth Proportional to 81.18, 111.93 and 53.51

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Solution

The fourth proportional to 81.18, 111.93 and 53.51 is: 73.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.18 : 111.93 = 53.51 : x
  2. Step 2: Convert to fraction form
    81.18/111.93 = 53.51/x
  3. Step 3: Cross multiply
    81.18x = 111.93 × 53.51
  4. Step 4: Simplify right side
    81.18x = 5,988.81
  5. Step 5: Solve for x
    x = 5,988.81/81.18
  6. Step 6: Final answer
    x = 73.77

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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.