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Finding the Fourth Proportional to 71.80, 99.02 and 57.90

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Solution

The fourth proportional to 71.80, 99.02 and 57.90 is: 79.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.80 : 99.02 = 57.90 : x
  2. Step 2: Convert to fraction form
    71.80/99.02 = 57.90/x
  3. Step 3: Cross multiply
    71.80x = 99.02 × 57.90
  4. Step 4: Simplify right side
    71.80x = 5,733.26
  5. Step 5: Solve for x
    x = 5,733.26/71.80
  6. Step 6: Final answer
    x = 79.85

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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.