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Finding the Fourth Proportional to 1,242.64, 1,864.19 and 420.69

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Solution

The fourth proportional to 1,242.64, 1,864.19 and 420.69 is: 631.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,242.64 : 1,864.19 = 420.69 : x
  2. Step 2: Convert to fraction form
    1,242.64/1,864.19 = 420.69/x
  3. Step 3: Cross multiply
    1,242.64x = 1,864.19 × 420.69
  4. Step 4: Simplify right side
    1,242.64x = 784,246.09
  5. Step 5: Solve for x
    x = 784,246.09/1,242.64
  6. Step 6: Final answer
    x = 631.12

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.