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Finding the Fourth Proportional to 290.81, 436.25 and 128.40

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Solution

The fourth proportional to 290.81, 436.25 and 128.40 is: 192.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    290.81 : 436.25 = 128.40 : x
  2. Step 2: Convert to fraction form
    290.81/436.25 = 128.40/x
  3. Step 3: Cross multiply
    290.81x = 436.25 × 128.40
  4. Step 4: Simplify right side
    290.81x = 56,014.82
  5. Step 5: Solve for x
    x = 56,014.82/290.81
  6. Step 6: Final answer
    x = 192.62

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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.