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Finding the Fourth Proportional to 124.92, 172.38 and 90

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Solution

The fourth proportional to 124.92, 172.38 and 90 is: 124.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    124.92 : 172.38 = 90 : x
  2. Step 2: Convert to fraction form
    124.92/172.38 = 90/x
  3. Step 3: Cross multiply
    124.92x = 172.38 × 90
  4. Step 4: Simplify right side
    124.92x = 15,514.20
  5. Step 5: Solve for x
    x = 15,514.20/124.92
  6. Step 6: Final answer
    x = 124.19

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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.