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Finding the Fourth Proportional to 838.76, 1,157.90 and 643.14

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Solution

The fourth proportional to 838.76, 1,157.90 and 643.14 is: 887.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    838.76 : 1,157.90 = 643.14 : x
  2. Step 2: Convert to fraction form
    838.76/1,157.90 = 643.14/x
  3. Step 3: Cross multiply
    838.76x = 1,157.90 × 643.14
  4. Step 4: Simplify right side
    838.76x = 744,688.59
  5. Step 5: Solve for x
    x = 744,688.59/838.76
  6. Step 6: Final answer
    x = 887.85

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Double scale
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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.