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Finding the Fourth Proportional to 72.99, 100.74 and 51.21

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Solution

The fourth proportional to 72.99, 100.74 and 51.21 is: 70.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.99 : 100.74 = 51.21 : x
  2. Step 2: Convert to fraction form
    72.99/100.74 = 51.21/x
  3. Step 3: Cross multiply
    72.99x = 100.74 × 51.21
  4. Step 4: Simplify right side
    72.99x = 5,158.90
  5. Step 5: Solve for x
    x = 5,158.90/72.99
  6. Step 6: Final answer
    x = 70.68

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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.