Answer:

Step-by-step explanation:
Answer:
yes
Step-by-step explanation:
Yes this triangle is right angled and can be justified using the Pythagorean theorem. The theorem states that:
. Substitute using the given values:
(9^2)+(12^2)=15^2
81 + 144 = 255
255 = 255.
It satisfies the theorem therefore it is a right angle triangle.
The expression 7•3x is not equal to the expression 21x. You might think that the two expressions are the same since 7x3 is 21 but the first expression is a dot product. This kind of expression includes the magnitude and direction of the vector in an expression, for example, <span>7•3x. The second expression, 21x, expresses only the magnitude and does not include the direction.</span>
You haven't included a diagram, however, if it's an isosceles triangle 2 of its sides will be the same and 1 will be different