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Finding the Fourth Proportional to 84.65, 126.36 and 78.57

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Solution

The fourth proportional to 84.65, 126.36 and 78.57 is: 117.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.65 : 126.36 = 78.57 : x
  2. Step 2: Convert to fraction form
    84.65/126.36 = 78.57/x
  3. Step 3: Cross multiply
    84.65x = 126.36 × 78.57
  4. Step 4: Simplify right side
    84.65x = 9,928.11
  5. Step 5: Solve for x
    x = 9,928.11/84.65
  6. Step 6: Final answer
    x = 117.29

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.