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Finding the Fourth Proportional to 256.80, 385.76 and 253.28

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Solution

The fourth proportional to 256.80, 385.76 and 253.28 is: 380.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    256.80 : 385.76 = 253.28 : x
  2. Step 2: Convert to fraction form
    256.80/385.76 = 253.28/x
  3. Step 3: Cross multiply
    256.80x = 385.76 × 253.28
  4. Step 4: Simplify right side
    256.80x = 97,705.29
  5. Step 5: Solve for x
    x = 97,705.29/256.80
  6. Step 6: Final answer
    x = 380.47

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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.