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Finding the Fourth Proportional to 312.58, 431.48 and 279.77

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Solution

The fourth proportional to 312.58, 431.48 and 279.77 is: 386.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.58 : 431.48 = 279.77 : x
  2. Step 2: Convert to fraction form
    312.58/431.48 = 279.77/x
  3. Step 3: Cross multiply
    312.58x = 431.48 × 279.77
  4. Step 4: Simplify right side
    312.58x = 120,715.16
  5. Step 5: Solve for x
    x = 120,715.16/312.58
  6. Step 6: Final answer
    x = 386.19

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.