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Finding the Fourth Proportional to 78.27, 108.09 and 64.50

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Solution

The fourth proportional to 78.27, 108.09 and 64.50 is: 89.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.27 : 108.09 = 64.50 : x
  2. Step 2: Convert to fraction form
    78.27/108.09 = 64.50/x
  3. Step 3: Cross multiply
    78.27x = 108.09 × 64.50
  4. Step 4: Simplify right side
    78.27x = 6,971.81
  5. Step 5: Solve for x
    x = 6,971.81/78.27
  6. Step 6: Final answer
    x = 89.07

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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.