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Finding the Fourth Proportional to 120, 180 and 118.40

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Solution

The fourth proportional to 120, 180 and 118.40 is: 177.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    120 : 180 = 118.40 : x
  2. Step 2: Convert to fraction form
    120/180 = 118.40/x
  3. Step 3: Cross multiply
    120x = 180 × 118.40
  4. Step 4: Simplify right side
    120x = 21,312
  5. Step 5: Solve for x
    x = 21,312/120
  6. Step 6: Final answer
    x = 177.60

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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.