Home / 55-82.49-20.78

Finding the Fourth Proportional to 55, 82.49 and 20.78

Calculator

Solution

The fourth proportional to 55, 82.49 and 20.78 is: 31.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    55 : 82.49 = 20.78 : x
  2. Step 2: Convert to fraction form
    55/82.49 = 20.78/x
  3. Step 3: Cross multiply
    55x = 82.49 × 20.78
  4. Step 4: Simplify right side
    55x = 1,714.14
  5. Step 5: Solve for x
    x = 1,714.14/55
  6. Step 6: Final answer
    x = 31.17

Related Problems

Find fourth proportional to 27.50, 41.25 and 10.39
Half scale
Find fourth proportional to 110, 164.98 and 41.56
Double scale
Find fourth proportional to 56, 83.99 and 21.78
Similar ratio
Find fourth proportional to 82.50, 123.74 and 31.17
1.5x scale

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.