Respuesta :

musiclover10045

Using the Pythagorean theorem:

X = sqrt(21^2 - 19^2)

X = sqrt(441 - 361)

X = sqrt(80)

X = 8.944

Rounded to the nearest tenth = 8.9

ap3813

Answer:

x = ~8.9

Step-by-step explanation:

a^2 + b^2 = c^2

c is the long side

a and b are the other two shorter sides

this means

x^2 + 19^2 = 21^2

x^2 + 361 = 441

x^2 = 441- 361

x^2 = 441- 361

x^2 = 80

square root of 80 = ~8.9

x = ~8.9