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Finding the Fourth Proportional to 985.70, 1,358.98 and 808

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Solution

The fourth proportional to 985.70, 1,358.98 and 808 is: 1,113.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    985.70 : 1,358.98 = 808 : x
  2. Step 2: Convert to fraction form
    985.70/1,358.98 = 808/x
  3. Step 3: Cross multiply
    985.70x = 1,358.98 × 808
  4. Step 4: Simplify right side
    985.70x = 1,098,055.84
  5. Step 5: Solve for x
    x = 1,098,055.84/985.70
  6. Step 6: Final answer
    x = 1,113.99

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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.