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Finding the Fourth Proportional to 124.79, 172.08 and 81.05

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Solution

The fourth proportional to 124.79, 172.08 and 81.05 is: 111.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    124.79 : 172.08 = 81.05 : x
  2. Step 2: Convert to fraction form
    124.79/172.08 = 81.05/x
  3. Step 3: Cross multiply
    124.79x = 172.08 × 81.05
  4. Step 4: Simplify right side
    124.79x = 13,947.08
  5. Step 5: Solve for x
    x = 13,947.08/124.79
  6. Step 6: Final answer
    x = 111.76

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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.