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Finding the Fourth Proportional to 72.90, 100.76 and 64.09

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Solution

The fourth proportional to 72.90, 100.76 and 64.09 is: 88.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.90 : 100.76 = 64.09 : x
  2. Step 2: Convert to fraction form
    72.90/100.76 = 64.09/x
  3. Step 3: Cross multiply
    72.90x = 100.76 × 64.09
  4. Step 4: Simplify right side
    72.90x = 6,457.14
  5. Step 5: Solve for x
    x = 6,457.14/72.90
  6. Step 6: Final answer
    x = 88.58

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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.