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Finding the Fourth Proportional to 153.28, 211.51 and 87.78

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Solution

The fourth proportional to 153.28, 211.51 and 87.78 is: 121.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    153.28 : 211.51 = 87.78 : x
  2. Step 2: Convert to fraction form
    153.28/211.51 = 87.78/x
  3. Step 3: Cross multiply
    153.28x = 211.51 × 87.78
  4. Step 4: Simplify right side
    153.28x = 18,566.35
  5. Step 5: Solve for x
    x = 18,566.35/153.28
  6. Step 6: Final answer
    x = 121.13

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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.