Finding the Fourth Proportional to 128.85, 177.63 and 79.70
Calculator
Solution
The fourth proportional to 128.85, 177.63 and 79.70 is: 109.87
Step by Step Solution
- Step 1: Write the proportion equation
128.85 : 177.63 = 79.70 : x - Step 2: Convert to fraction form
128.85/177.63 = 79.70/x - Step 3: Cross multiply
128.85x = 177.63 × 79.70 - Step 4: Simplify right side
128.85x = 14,156.22 - Step 5: Solve for x
x = 14,156.22/128.85 - Step 6: Final answer
x = 109.87
Related Problems
Find fourth proportional to 64.43, 88.82 and 39.85
Half scale
Find fourth proportional to 257.70, 355.26 and 159.39
Double scale
Find fourth proportional to 129.85, 179.01 and 80.70
Similar ratio
Find fourth proportional to 193.28, 266.45 and 119.54
1.5x scale
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.