Home / 153.80-212.10-121

Finding the Fourth Proportional to 153.80, 212.10 and 121

Calculator

Solution

The fourth proportional to 153.80, 212.10 and 121 is: 166.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    153.80 : 212.10 = 121 : x
  2. Step 2: Convert to fraction form
    153.80/212.10 = 121/x
  3. Step 3: Cross multiply
    153.80x = 212.10 × 121
  4. Step 4: Simplify right side
    153.80x = 25,664.10
  5. Step 5: Solve for x
    x = 25,664.10/153.80
  6. Step 6: Final answer
    x = 166.87

Related Problems

Find fourth proportional to 76.90, 106.05 and 60.50
Half scale
Find fourth proportional to 307.60, 424.20 and 242
Double scale
Find fourth proportional to 154.80, 213.48 and 122
Similar ratio
Find fourth proportional to 230.70, 318.15 and 181.50
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.