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Finding the Fourth Proportional to 219, 328.50 and 90.78

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Solution

The fourth proportional to 219, 328.50 and 90.78 is: 136.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    219 : 328.50 = 90.78 : x
  2. Step 2: Convert to fraction form
    219/328.50 = 90.78/x
  3. Step 3: Cross multiply
    219x = 328.50 × 90.78
  4. Step 4: Simplify right side
    219x = 29,821.23
  5. Step 5: Solve for x
    x = 29,821.23/219
  6. Step 6: Final answer
    x = 136.17

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.