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Finding the Fourth Proportional to 643.79, 889.09 and 486.16

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Solution

The fourth proportional to 643.79, 889.09 and 486.16 is: 671.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.79 : 889.09 = 486.16 : x
  2. Step 2: Convert to fraction form
    643.79/889.09 = 486.16/x
  3. Step 3: Cross multiply
    643.79x = 889.09 × 486.16
  4. Step 4: Simplify right side
    643.79x = 432,239.99
  5. Step 5: Solve for x
    x = 432,239.99/643.79
  6. Step 6: Final answer
    x = 671.40

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1.5x scale

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.