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Finding the Fourth Proportional to 279.76, 419.66 and 87.40

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Solution

The fourth proportional to 279.76, 419.66 and 87.40 is: 131.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    279.76 : 419.66 = 87.40 : x
  2. Step 2: Convert to fraction form
    279.76/419.66 = 87.40/x
  3. Step 3: Cross multiply
    279.76x = 419.66 × 87.40
  4. Step 4: Simplify right side
    279.76x = 36,678.28
  5. Step 5: Solve for x
    x = 36,678.28/279.76
  6. Step 6: Final answer
    x = 131.11

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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.