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Finding the Fourth Proportional to 72.42, 99.99 and 64.66

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Solution

The fourth proportional to 72.42, 99.99 and 64.66 is: 89.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.42 : 99.99 = 64.66 : x
  2. Step 2: Convert to fraction form
    72.42/99.99 = 64.66/x
  3. Step 3: Cross multiply
    72.42x = 99.99 × 64.66
  4. Step 4: Simplify right side
    72.42x = 6,465.35
  5. Step 5: Solve for x
    x = 6,465.35/72.42
  6. Step 6: Final answer
    x = 89.28

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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.