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Finding the Fourth Proportional to 498.72, 687.48 and 420

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Solution

The fourth proportional to 498.72, 687.48 and 420 is: 578.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    498.72 : 687.48 = 420 : x
  2. Step 2: Convert to fraction form
    498.72/687.48 = 420/x
  3. Step 3: Cross multiply
    498.72x = 687.48 × 420
  4. Step 4: Simplify right side
    498.72x = 288,741.60
  5. Step 5: Solve for x
    x = 288,741.60/498.72
  6. Step 6: Final answer
    x = 578.97

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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.