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Finding the Fourth Proportional to 1,242.99, 1,864.65 and 421.05

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Solution

The fourth proportional to 1,242.99, 1,864.65 and 421.05 is: 631.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,242.99 : 1,864.65 = 421.05 : x
  2. Step 2: Convert to fraction form
    1,242.99/1,864.65 = 421.05/x
  3. Step 3: Cross multiply
    1,242.99x = 1,864.65 × 421.05
  4. Step 4: Simplify right side
    1,242.99x = 785,110.88
  5. Step 5: Solve for x
    x = 785,110.88/1,242.99
  6. Step 6: Final answer
    x = 631.63

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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.