Home / 389.95-538.13-215.30

Finding the Fourth Proportional to 389.95, 538.13 and 215.30

Calculator

Solution

The fourth proportional to 389.95, 538.13 and 215.30 is: 297.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    389.95 : 538.13 = 215.30 : x
  2. Step 2: Convert to fraction form
    389.95/538.13 = 215.30/x
  3. Step 3: Cross multiply
    389.95x = 538.13 × 215.30
  4. Step 4: Simplify right side
    389.95x = 115,859.39
  5. Step 5: Solve for x
    x = 115,859.39/389.95
  6. Step 6: Final answer
    x = 297.11

Related Problems

Find fourth proportional to 194.98, 269.07 and 107.65
Half scale
Find fourth proportional to 779.90, 1,076.26 and 430.60
Double scale
Find fourth proportional to 390.95, 539.51 and 216.30
Similar ratio
Find fourth proportional to 584.93, 807.20 and 322.95
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.