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Finding the Fourth Proportional to 279.84, 420 and 258.24

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Solution

The fourth proportional to 279.84, 420 and 258.24 is: 387.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    279.84 : 420 = 258.24 : x
  2. Step 2: Convert to fraction form
    279.84/420 = 258.24/x
  3. Step 3: Cross multiply
    279.84x = 420 × 258.24
  4. Step 4: Simplify right side
    279.84x = 108,460.80
  5. Step 5: Solve for x
    x = 108,460.80/279.84
  6. Step 6: Final answer
    x = 387.58

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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.