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Finding the Fourth Proportional to 72.40, 99.80 and 57.82

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Solution

The fourth proportional to 72.40, 99.80 and 57.82 is: 79.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.40 : 99.80 = 57.82 : x
  2. Step 2: Convert to fraction form
    72.40/99.80 = 57.82/x
  3. Step 3: Cross multiply
    72.40x = 99.80 × 57.82
  4. Step 4: Simplify right side
    72.40x = 5,770.44
  5. Step 5: Solve for x
    x = 5,770.44/72.40
  6. Step 6: Final answer
    x = 79.70

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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.