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Finding the Fourth Proportional to 521.65, 719.75 and 311.90

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Solution

The fourth proportional to 521.65, 719.75 and 311.90 is: 430.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    521.65 : 719.75 = 311.90 : x
  2. Step 2: Convert to fraction form
    521.65/719.75 = 311.90/x
  3. Step 3: Cross multiply
    521.65x = 719.75 × 311.90
  4. Step 4: Simplify right side
    521.65x = 224,490.03
  5. Step 5: Solve for x
    x = 224,490.03/521.65
  6. Step 6: Final answer
    x = 430.35

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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.