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Finding the Fourth Proportional to 125.40, 172.98 and 90.39

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Solution

The fourth proportional to 125.40, 172.98 and 90.39 is: 124.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    125.40 : 172.98 = 90.39 : x
  2. Step 2: Convert to fraction form
    125.40/172.98 = 90.39/x
  3. Step 3: Cross multiply
    125.40x = 172.98 × 90.39
  4. Step 4: Simplify right side
    125.40x = 15,635.66
  5. Step 5: Solve for x
    x = 15,635.66/125.40
  6. Step 6: Final answer
    x = 124.69

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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.