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Finding the Fourth Proportional to 319.60, 438.08 and 315.40

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Solution

The fourth proportional to 319.60, 438.08 and 315.40 is: 432.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    319.60 : 438.08 = 315.40 : x
  2. Step 2: Convert to fraction form
    319.60/438.08 = 315.40/x
  3. Step 3: Cross multiply
    319.60x = 438.08 × 315.40
  4. Step 4: Simplify right side
    319.60x = 138,170.43
  5. Step 5: Solve for x
    x = 138,170.43/319.60
  6. Step 6: Final answer
    x = 432.32

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.