Home / 211.42-291.72-128.51

Finding the Fourth Proportional to 211.42, 291.72 and 128.51

Calculator

Solution

The fourth proportional to 211.42, 291.72 and 128.51 is: 177.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.42 : 291.72 = 128.51 : x
  2. Step 2: Convert to fraction form
    211.42/291.72 = 128.51/x
  3. Step 3: Cross multiply
    211.42x = 291.72 × 128.51
  4. Step 4: Simplify right side
    211.42x = 37,488.94
  5. Step 5: Solve for x
    x = 37,488.94/211.42
  6. Step 6: Final answer
    x = 177.32

Related Problems

Find fourth proportional to 105.71, 145.86 and 64.26
Half scale
Find fourth proportional to 422.84, 583.44 and 257.02
Double scale
Find fourth proportional to 212.42, 293.10 and 129.51
Similar ratio
Find fourth proportional to 317.13, 437.58 and 192.77
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.