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Finding the Fourth Proportional to 521.28, 719.28 and 311.40

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Solution

The fourth proportional to 521.28, 719.28 and 311.40 is: 429.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    521.28 : 719.28 = 311.40 : x
  2. Step 2: Convert to fraction form
    521.28/719.28 = 311.40/x
  3. Step 3: Cross multiply
    521.28x = 719.28 × 311.40
  4. Step 4: Simplify right side
    521.28x = 223,983.79
  5. Step 5: Solve for x
    x = 223,983.79/521.28
  6. Step 6: Final answer
    x = 429.68

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1.5x scale

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.