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Finding the Fourth Proportional to 291.59, 399.79 and 286.40

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Solution

The fourth proportional to 291.59, 399.79 and 286.40 is: 392.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    291.59 : 399.79 = 286.40 : x
  2. Step 2: Convert to fraction form
    291.59/399.79 = 286.40/x
  3. Step 3: Cross multiply
    291.59x = 399.79 × 286.40
  4. Step 4: Simplify right side
    291.59x = 114,499.86
  5. Step 5: Solve for x
    x = 114,499.86/291.59
  6. Step 6: Final answer
    x = 392.67

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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.