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Finding the Fourth Proportional to 84.79, 117.05 and 57.15

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Solution

The fourth proportional to 84.79, 117.05 and 57.15 is: 78.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.79 : 117.05 = 57.15 : x
  2. Step 2: Convert to fraction form
    84.79/117.05 = 57.15/x
  3. Step 3: Cross multiply
    84.79x = 117.05 × 57.15
  4. Step 4: Simplify right side
    84.79x = 6,688.82
  5. Step 5: Solve for x
    x = 6,688.82/84.79
  6. Step 6: Final answer
    x = 78.89

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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.