Answer:
a) 20, 21, 28 : acute
b) 3, 6, 4 : obtuse
c) 8, 12, 15 : obtuse
Step-by-step explanation:
You can see if a triangle is acute, obtuse, or right using the Pythagorean theorem as follows:
If [tex]a^2+b^2=c^2[/tex] , then the triangle is right.
If [tex]a^2+b^2>c^2[/tex] , then the triangle is acute.
If [tex]a^2+b^2<c^2[/tex] , then the triangle is obtuse.
Solve each to find if the given lengths form an acute, obtuse, or right triangle ( The biggest number is the hypotenuse length, since the hypotenuse is always the longest side in a triangle. This is represented by c):
a) 20, 21, 28
Insert numbers, using 28 as c:
[tex]20^2+21^2[/tex]_[tex]28^2[/tex]
Simplify exponents ([tex]x^2=x*x[/tex]):
[tex]400+441[/tex]_[tex]784[/tex]
Simplify addition:
[tex]841[/tex]_[tex]784[/tex]
Identify relationship:
[tex]841>784[/tex]
The sum of the squares of a and b is greater than the square of c. This triangle is acute.
b) 3, 6, 4
Insert numbers, using 6 as c:
[tex]3^2+4^2[/tex]_[tex]6^2[/tex]
Simplify exponents:
[tex]9+16[/tex]_[tex]36[/tex]
Simplify addition:
[tex]25[/tex]_[tex]36[/tex]
Identify relationship:
[tex]25<36[/tex]
The sum of the squares of a and b is less than the square of c. This triangle is obtuse.
c) 8, 12, 15
Insert numbers, using 15 as c:
[tex]8^2+12^2[/tex]_[tex]15^2[/tex]
Simplify exponents:
[tex]64+144[/tex]_[tex]225[/tex]
Simplify addition:
[tex]208[/tex]_[tex]225[/tex]
Identify relationship:
[tex]208<225[/tex]
The sum of the squares of a and b is less than the square of c. This triangle is obtuse.
:Done.
