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Finding the Fourth Proportional to 123.80, 170.75 and 72.05

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Solution

The fourth proportional to 123.80, 170.75 and 72.05 is: 99.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    123.80 : 170.75 = 72.05 : x
  2. Step 2: Convert to fraction form
    123.80/170.75 = 72.05/x
  3. Step 3: Cross multiply
    123.80x = 170.75 × 72.05
  4. Step 4: Simplify right side
    123.80x = 12,301.86
  5. Step 5: Solve for x
    x = 12,301.86/123.80
  6. Step 6: Final answer
    x = 99.37

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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.