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Finding the Fourth Proportional to 811.68, 1,117.80 and 713.40

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Solution

The fourth proportional to 811.68, 1,117.80 and 713.40 is: 982.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.68 : 1,117.80 = 713.40 : x
  2. Step 2: Convert to fraction form
    811.68/1,117.80 = 713.40/x
  3. Step 3: Cross multiply
    811.68x = 1,117.80 × 713.40
  4. Step 4: Simplify right side
    811.68x = 797,438.52
  5. Step 5: Solve for x
    x = 797,438.52/811.68
  6. Step 6: Final answer
    x = 982.45

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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.