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Finding the Fourth Proportional to 643.88, 888.60 and 378.38

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Solution

The fourth proportional to 643.88, 888.60 and 378.38 is: 522.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.88 : 888.60 = 378.38 : x
  2. Step 2: Convert to fraction form
    643.88/888.60 = 378.38/x
  3. Step 3: Cross multiply
    643.88x = 888.60 × 378.38
  4. Step 4: Simplify right side
    643.88x = 336,228.47
  5. Step 5: Solve for x
    x = 336,228.47/643.88
  6. Step 6: Final answer
    x = 522.19

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Double scale
Find fourth proportional to 644.88, 889.98 and 379.38
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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.