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Finding the Fourth Proportional to 455.29, 679.63 and 421.45

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Solution

The fourth proportional to 455.29, 679.63 and 421.45 is: 629.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    455.29 : 679.63 = 421.45 : x
  2. Step 2: Convert to fraction form
    455.29/679.63 = 421.45/x
  3. Step 3: Cross multiply
    455.29x = 679.63 × 421.45
  4. Step 4: Simplify right side
    455.29x = 286,430.06
  5. Step 5: Solve for x
    x = 286,430.06/455.29
  6. Step 6: Final answer
    x = 629.12

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.