Finding the Fourth Proportional to 81.19, 121.79 and 69.74
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Solution
The fourth proportional to 81.19, 121.79 and 69.74 is: 104.62
Step by Step Solution
- Step 1: Write the proportion equation
81.19 : 121.79 = 69.74 : x - Step 2: Convert to fraction form
81.19/121.79 = 69.74/x - Step 3: Cross multiply
81.19x = 121.79 × 69.74 - Step 4: Simplify right side
81.19x = 8,493.81 - Step 5: Solve for x
x = 8,493.81/81.19 - Step 6: Final answer
x = 104.62
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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.