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Finding the Fourth Proportional to 938.64, 1,294.10 and 643.40

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Solution

The fourth proportional to 938.64, 1,294.10 and 643.40 is: 887.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    938.64 : 1,294.10 = 643.40 : x
  2. Step 2: Convert to fraction form
    938.64/1,294.10 = 643.40/x
  3. Step 3: Cross multiply
    938.64x = 1,294.10 × 643.40
  4. Step 4: Simplify right side
    938.64x = 832,623.94
  5. Step 5: Solve for x
    x = 832,623.94/938.64
  6. Step 6: Final answer
    x = 887.05

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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.