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Finding the Fourth Proportional to 290.50, 435.80 and 128.18

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Solution

The fourth proportional to 290.50, 435.80 and 128.18 is: 192.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    290.50 : 435.80 = 128.18 : x
  2. Step 2: Convert to fraction form
    290.50/435.80 = 128.18/x
  3. Step 3: Cross multiply
    290.50x = 435.80 × 128.18
  4. Step 4: Simplify right side
    290.50x = 55,862.25
  5. Step 5: Solve for x
    x = 55,862.25/290.50
  6. Step 6: Final answer
    x = 192.30

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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.