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Finding the Fourth Proportional to 719.43, 991.42 and 718.21

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Solution

The fourth proportional to 719.43, 991.42 and 718.21 is: 989.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    719.43 : 991.42 = 718.21 : x
  2. Step 2: Convert to fraction form
    719.43/991.42 = 718.21/x
  3. Step 3: Cross multiply
    719.43x = 991.42 × 718.21
  4. Step 4: Simplify right side
    719.43x = 712,047.76
  5. Step 5: Solve for x
    x = 712,047.76/719.43
  6. Step 6: Final answer
    x = 989.74

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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.