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Finding the Fourth Proportional to 390.29, 538.19 and 315.53

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Solution

The fourth proportional to 390.29, 538.19 and 315.53 is: 435.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.29 : 538.19 = 315.53 : x
  2. Step 2: Convert to fraction form
    390.29/538.19 = 315.53/x
  3. Step 3: Cross multiply
    390.29x = 538.19 × 315.53
  4. Step 4: Simplify right side
    390.29x = 169,815.80
  5. Step 5: Solve for x
    x = 169,815.80/390.29
  6. Step 6: Final answer
    x = 435.10

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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.