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Finding the Fourth Proportional to 76.31, 105.21 and 64.00

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Solution

The fourth proportional to 76.31, 105.21 and 64.00 is: 88.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.31 : 105.21 = 64.00 : x
  2. Step 2: Convert to fraction form
    76.31/105.21 = 64.00/x
  3. Step 3: Cross multiply
    76.31x = 105.21 × 64.00
  4. Step 4: Simplify right side
    76.31x = 6,733.57
  5. Step 5: Solve for x
    x = 6,733.57/76.31
  6. Step 6: Final answer
    x = 88.24

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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.