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Finding the Fourth Proportional to 71.84, 99.15 and 57.40

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Solution

The fourth proportional to 71.84, 99.15 and 57.40 is: 79.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.84 : 99.15 = 57.40 : x
  2. Step 2: Convert to fraction form
    71.84/99.15 = 57.40/x
  3. Step 3: Cross multiply
    71.84x = 99.15 × 57.40
  4. Step 4: Simplify right side
    71.84x = 5,691.21
  5. Step 5: Solve for x
    x = 5,691.21/71.84
  6. Step 6: Final answer
    x = 79.22

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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.