Finding the Fourth Proportional to 139.15, 208.70 and 87.70
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Solution
The fourth proportional to 139.15, 208.70 and 87.70 is: 131.53
Step by Step Solution
- Step 1: Write the proportion equation
139.15 : 208.70 = 87.70 : x - Step 2: Convert to fraction form
139.15/208.70 = 87.70/x - Step 3: Cross multiply
139.15x = 208.70 × 87.70 - Step 4: Simplify right side
139.15x = 18,302.99 - Step 5: Solve for x
x = 18,302.99/139.15 - Step 6: Final answer
x = 131.53
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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.