Question #7922f

2 Answers
Nov 29, 2017

Yes

Explanation:

Using Pythagorus

For a right angled triangle #h^2 = a^2 + b^2# where #h# is the hypotenuse and #a# and #b# are the other two sides

conversely if the sum of the squares of #a# and #b# = the square of the hypotenuse, then the triangle must be right-angled.

Substitute in what we know
#15^2 = 9^2 + 12^2#

Simplify
#225 = 81 + 144 = 225#

Therefore the triangle is a right-angled triangle

Nov 29, 2017

#"right triangle"#

Explanation:

#"using the "color(blue)"converse theorem of Pythagoras"#

#"if the longest side squared is equal to the sum of the "#
#"other two sides squared then it is a right triangle"#

#rArr15^5=225larrcolor(blue)"longest side squared"#

#9^2+12^2=81+144=225#

#"since "15^2=9^2+12^2#

#"then it is a right triangle"#