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Finding the Fourth Proportional to 124.80, 172.34 and 100.40

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Solution

The fourth proportional to 124.80, 172.34 and 100.40 is: 138.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    124.80 : 172.34 = 100.40 : x
  2. Step 2: Convert to fraction form
    124.80/172.34 = 100.40/x
  3. Step 3: Cross multiply
    124.80x = 172.34 × 100.40
  4. Step 4: Simplify right side
    124.80x = 17,301.57
  5. Step 5: Solve for x
    x = 17,301.57/124.80
  6. Step 6: Final answer
    x = 138.63

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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.