Finding the Fourth Proportional to 100.68, 139.12 and 90.45
Calculator
Solution
The fourth proportional to 100.68, 139.12 and 90.45 is: 124.99
Step by Step Solution
- Step 1: Write the proportion equation
100.68 : 139.12 = 90.45 : x - Step 2: Convert to fraction form
100.68/139.12 = 90.45/x - Step 3: Cross multiply
100.68x = 139.12 × 90.45 - Step 4: Simplify right side
100.68x = 12,583.18 - Step 5: Solve for x
x = 12,583.18/100.68 - Step 6: Final answer
x = 124.99
Related Problems
Find fourth proportional to 50.34, 69.56 and 45.23
Half scale
Find fourth proportional to 201.35, 278.24 and 180.90
Double scale
Find fourth proportional to 101.68, 140.50 and 91.45
Similar ratio
Find fourth proportional to 151.01, 208.68 and 135.68
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.