Home / 211.39-291.69-122.80

Finding the Fourth Proportional to 211.39, 291.69 and 122.80

Calculator

Solution

The fourth proportional to 211.39, 291.69 and 122.80 is: 169.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.39 : 291.69 = 122.80 : x
  2. Step 2: Convert to fraction form
    211.39/291.69 = 122.80/x
  3. Step 3: Cross multiply
    211.39x = 291.69 × 122.80
  4. Step 4: Simplify right side
    211.39x = 35,818.44
  5. Step 5: Solve for x
    x = 35,818.44/211.39
  6. Step 6: Final answer
    x = 169.44

Related Problems

Find fourth proportional to 105.70, 145.85 and 61.40
Half scale
Find fourth proportional to 422.78, 583.38 and 245.59
Double scale
Find fourth proportional to 212.39, 293.07 and 123.80
Similar ratio
Find fourth proportional to 317.09, 437.54 and 184.19
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.