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Finding the Fourth Proportional to 86.32, 128.90 and 64.96

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Solution

The fourth proportional to 86.32, 128.90 and 64.96 is: 97.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.32 : 128.90 = 64.96 : x
  2. Step 2: Convert to fraction form
    86.32/128.90 = 64.96/x
  3. Step 3: Cross multiply
    86.32x = 128.90 × 64.96
  4. Step 4: Simplify right side
    86.32x = 8,373.34
  5. Step 5: Solve for x
    x = 8,373.34/86.32
  6. Step 6: Final answer
    x = 97.00

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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.