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Finding the Fourth Proportional to 55.65, 76.80 and 31.10

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Solution

The fourth proportional to 55.65, 76.80 and 31.10 is: 42.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    55.65 : 76.80 = 31.10 : x
  2. Step 2: Convert to fraction form
    55.65/76.80 = 31.10/x
  3. Step 3: Cross multiply
    55.65x = 76.80 × 31.10
  4. Step 4: Simplify right side
    55.65x = 2,388.10
  5. Step 5: Solve for x
    x = 2,388.10/55.65
  6. Step 6: Final answer
    x = 42.91

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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.