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Finding the Fourth Proportional to 65.30, 90.15 and 40.40

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Solution

The fourth proportional to 65.30, 90.15 and 40.40 is: 55.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    65.30 : 90.15 = 40.40 : x
  2. Step 2: Convert to fraction form
    65.30/90.15 = 40.40/x
  3. Step 3: Cross multiply
    65.30x = 90.15 × 40.40
  4. Step 4: Simplify right side
    65.30x = 3,642.18
  5. Step 5: Solve for x
    x = 3,642.18/65.30
  6. Step 6: Final answer
    x = 55.78

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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.