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Finding the Fourth Proportional to 997.70, 1,376.20 and 643.51

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Solution

The fourth proportional to 997.70, 1,376.20 and 643.51 is: 887.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    997.70 : 1,376.20 = 643.51 : x
  2. Step 2: Convert to fraction form
    997.70/1,376.20 = 643.51/x
  3. Step 3: Cross multiply
    997.70x = 1,376.20 × 643.51
  4. Step 4: Simplify right side
    997.70x = 885,598.46
  5. Step 5: Solve for x
    x = 885,598.46/997.70
  6. Step 6: Final answer
    x = 887.64

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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.