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Finding the Fourth Proportional to 287.78, 431.98 and 253.76

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Solution

The fourth proportional to 287.78, 431.98 and 253.76 is: 380.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.78 : 431.98 = 253.76 : x
  2. Step 2: Convert to fraction form
    287.78/431.98 = 253.76/x
  3. Step 3: Cross multiply
    287.78x = 431.98 × 253.76
  4. Step 4: Simplify right side
    287.78x = 109,619.24
  5. Step 5: Solve for x
    x = 109,619.24/287.78
  6. Step 6: Final answer
    x = 380.91

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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.