Home / 145.81-217.65-128.51

Finding the Fourth Proportional to 145.81, 217.65 and 128.51

Calculator

Solution

The fourth proportional to 145.81, 217.65 and 128.51 is: 191.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    145.81 : 217.65 = 128.51 : x
  2. Step 2: Convert to fraction form
    145.81/217.65 = 128.51/x
  3. Step 3: Cross multiply
    145.81x = 217.65 × 128.51
  4. Step 4: Simplify right side
    145.81x = 27,970.75
  5. Step 5: Solve for x
    x = 27,970.75/145.81
  6. Step 6: Final answer
    x = 191.83

Related Problems

Find fourth proportional to 72.91, 108.83 and 64.26
Half scale
Find fourth proportional to 291.62, 435.30 and 257.03
Double scale
Find fourth proportional to 146.81, 219.14 and 129.51
Similar ratio
Find fourth proportional to 218.72, 326.48 and 192.77
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.