In a right angled triangle, the hypotenus is (3x + 2) cm long. If the other two sides are (x + 3) cm and 3x cm how do you find x?

1 Answer
Jun 1, 2018

x=1" or "x=5x=1 or x=5

Explanation:

"since they are right angled triangles we can use"since they are right angled triangles we can use
color(blue)"Pythagoras' theorem"Pythagoras' theorem

"the square on the hyotenuse "="sum of squares on the"the square on the hyotenuse =sum of squares on the
color(white)(xxxxxxxxxxxxxxxxxxxxxx)"other 2 sides"×××××××××××other 2 sides

(3x+2)^2=(x+3)^2+(3x)^2(3x+2)2=(x+3)2+(3x)2

cancel(9x^2)+12x+4=x^2+6x+9cancel(+9x^2)

"subtract "12x+4" from both sides"

0=x^2-6x+5

0=(x-1)(x-5)

x-1=0rArrx=1

x-5=0rArrx=5

"substitute these values into the given sides"

"to obtain "3,4,5 " or "8,15,17

"both well known "color(blue)"Pythagorean triples"