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Finding the Fourth Proportional to 1,188.40, 1,640.40 and 716.56

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Solution

The fourth proportional to 1,188.40, 1,640.40 and 716.56 is: 989.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,188.40 : 1,640.40 = 716.56 : x
  2. Step 2: Convert to fraction form
    1,188.40/1,640.40 = 716.56/x
  3. Step 3: Cross multiply
    1,188.40x = 1,640.40 × 716.56
  4. Step 4: Simplify right side
    1,188.40x = 1,175,445.02
  5. Step 5: Solve for x
    x = 1,175,445.02/1,188.40
  6. Step 6: Final answer
    x = 989.10

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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.