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Finding the Fourth Proportional to 402.90, 555.75 and 315.78

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Solution

The fourth proportional to 402.90, 555.75 and 315.78 is: 435.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    402.90 : 555.75 = 315.78 : x
  2. Step 2: Convert to fraction form
    402.90/555.75 = 315.78/x
  3. Step 3: Cross multiply
    402.90x = 555.75 × 315.78
  4. Step 4: Simplify right side
    402.90x = 175,494.74
  5. Step 5: Solve for x
    x = 175,494.74/402.90
  6. Step 6: Final answer
    x = 435.58

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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.