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Finding the Fourth Proportional to 78.84, 109.08 and 64.26

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Solution

The fourth proportional to 78.84, 109.08 and 64.26 is: 88.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.84 : 109.08 = 64.26 : x
  2. Step 2: Convert to fraction form
    78.84/109.08 = 64.26/x
  3. Step 3: Cross multiply
    78.84x = 109.08 × 64.26
  4. Step 4: Simplify right side
    78.84x = 7,009.48
  5. Step 5: Solve for x
    x = 7,009.48/78.84
  6. Step 6: Final answer
    x = 88.91

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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.