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Finding the Fourth Proportional to 153.95, 212.43 and 91.78

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Solution

The fourth proportional to 153.95, 212.43 and 91.78 is: 126.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    153.95 : 212.43 = 91.78 : x
  2. Step 2: Convert to fraction form
    153.95/212.43 = 91.78/x
  3. Step 3: Cross multiply
    153.95x = 212.43 × 91.78
  4. Step 4: Simplify right side
    153.95x = 19,495.76
  5. Step 5: Solve for x
    x = 19,495.76/153.95
  6. Step 6: Final answer
    x = 126.64

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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.