Finding the Fourth Proportional to 90.99, 135.87 and 86.31
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Solution
The fourth proportional to 90.99, 135.87 and 86.31 is: 128.88
Step by Step Solution
- Step 1: Write the proportion equation
90.99 : 135.87 = 86.31 : x - Step 2: Convert to fraction form
90.99/135.87 = 86.31/x - Step 3: Cross multiply
90.99x = 135.87 × 86.31 - Step 4: Simplify right side
90.99x = 11,726.48 - Step 5: Solve for x
x = 11,726.48/90.99 - Step 6: Final answer
x = 128.88
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Why These Related Problems?
These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.