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Finding the Fourth Proportional to 253.80, 380.40 and 99.65

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Solution

The fourth proportional to 253.80, 380.40 and 99.65 is: 149.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    253.80 : 380.40 = 99.65 : x
  2. Step 2: Convert to fraction form
    253.80/380.40 = 99.65/x
  3. Step 3: Cross multiply
    253.80x = 380.40 × 99.65
  4. Step 4: Simplify right side
    253.80x = 37,904.96
  5. Step 5: Solve for x
    x = 37,904.96/253.80
  6. Step 6: Final answer
    x = 149.35

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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.