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Finding the Fourth Proportional to 1,245.90, 1,719.32 and 686.36

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Solution

The fourth proportional to 1,245.90, 1,719.32 and 686.36 is: 947.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,245.90 : 1,719.32 = 686.36 : x
  2. Step 2: Convert to fraction form
    1,245.90/1,719.32 = 686.36/x
  3. Step 3: Cross multiply
    1,245.90x = 1,719.32 × 686.36
  4. Step 4: Simplify right side
    1,245.90x = 1,180,072.48
  5. Step 5: Solve for x
    x = 1,180,072.48/1,245.90
  6. Step 6: Final answer
    x = 947.16

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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.