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Finding the Fourth Proportional to 72.63, 99.70 and 66.15

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Solution

The fourth proportional to 72.63, 99.70 and 66.15 is: 90.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.63 : 99.70 = 66.15 : x
  2. Step 2: Convert to fraction form
    72.63/99.70 = 66.15/x
  3. Step 3: Cross multiply
    72.63x = 99.70 × 66.15
  4. Step 4: Simplify right side
    72.63x = 6,594.99
  5. Step 5: Solve for x
    x = 6,594.99/72.63
  6. Step 6: Final answer
    x = 90.80

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.