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Finding the Fourth Proportional to 718.72, 991.20 and 486.16

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Solution

The fourth proportional to 718.72, 991.20 and 486.16 is: 670.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    718.72 : 991.20 = 486.16 : x
  2. Step 2: Convert to fraction form
    718.72/991.20 = 486.16/x
  3. Step 3: Cross multiply
    718.72x = 991.20 × 486.16
  4. Step 4: Simplify right side
    718.72x = 481,881.79
  5. Step 5: Solve for x
    x = 481,881.79/718.72
  6. Step 6: Final answer
    x = 670.47

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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.