Home / 631.31-870.35-421.49

Finding the Fourth Proportional to 631.31, 870.35 and 421.49

Calculator

Solution

The fourth proportional to 631.31, 870.35 and 421.49 is: 581.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    631.31 : 870.35 = 421.49 : x
  2. Step 2: Convert to fraction form
    631.31/870.35 = 421.49/x
  3. Step 3: Cross multiply
    631.31x = 870.35 × 421.49
  4. Step 4: Simplify right side
    631.31x = 366,843.89
  5. Step 5: Solve for x
    x = 366,843.89/631.31
  6. Step 6: Final answer
    x = 581.09

Related Problems

Find fourth proportional to 315.65, 435.17 and 210.75
Half scale
Find fourth proportional to 1,262.61, 1,740.69 and 842.99
Double scale
Find fourth proportional to 632.31, 871.72 and 422.49
Similar ratio
Find fourth proportional to 946.96, 1,305.52 and 632.24
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.