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Finding the Fourth Proportional to 743.60, 1,115.20 and 256.80

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Solution

The fourth proportional to 743.60, 1,115.20 and 256.80 is: 385.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    743.60 : 1,115.20 = 256.80 : x
  2. Step 2: Convert to fraction form
    743.60/1,115.20 = 256.80/x
  3. Step 3: Cross multiply
    743.60x = 1,115.20 × 256.80
  4. Step 4: Simplify right side
    743.60x = 286,383.36
  5. Step 5: Solve for x
    x = 286,383.36/743.60
  6. Step 6: Final answer
    x = 385.13

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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.