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Finding the Fourth Proportional to 85.78, 118.40 and 53.03

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Solution

The fourth proportional to 85.78, 118.40 and 53.03 is: 73.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.78 : 118.40 = 53.03 : x
  2. Step 2: Convert to fraction form
    85.78/118.40 = 53.03/x
  3. Step 3: Cross multiply
    85.78x = 118.40 × 53.03
  4. Step 4: Simplify right side
    85.78x = 6,278.75
  5. Step 5: Solve for x
    x = 6,278.75/85.78
  6. Step 6: Final answer
    x = 73.20

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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.