Finding the Fourth Proportional to 81.09, 121.35 and 69.21
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Solution
The fourth proportional to 81.09, 121.35 and 69.21 is: 103.57
Step by Step Solution
- Step 1: Write the proportion equation
81.09 : 121.35 = 69.21 : x - Step 2: Convert to fraction form
81.09/121.35 = 69.21/x - Step 3: Cross multiply
81.09x = 121.35 × 69.21 - Step 4: Simplify right side
81.09x = 8,398.63 - Step 5: Solve for x
x = 8,398.63/81.09 - Step 6: Final answer
x = 103.57
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Why These Related Problems?
These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.