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Finding the Fourth Proportional to 78.40, 117.56 and 37.81

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Solution

The fourth proportional to 78.40, 117.56 and 37.81 is: 56.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.40 : 117.56 = 37.81 : x
  2. Step 2: Convert to fraction form
    78.40/117.56 = 37.81/x
  3. Step 3: Cross multiply
    78.40x = 117.56 × 37.81
  4. Step 4: Simplify right side
    78.40x = 4,444.74
  5. Step 5: Solve for x
    x = 4,444.74/78.40
  6. Step 6: Final answer
    x = 56.69

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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.