Answer:
a =
Step-by-step explanation:
Using Pythagoras' identity in the right triangle.
The square on the hypotenuse is equal to the sum of the squares on the other 2 sides, that is
a² + 9² = 12²
a² + 81 = 144 ( subtract 81 from both sides )
a² = 63 ( take square root of both sides )
a =
Given:
The figure of a triangle.
To find:
The missing length.
Solution:
Let x be the missing length.
Basic proportionality theorem(BPT): According to this theorem, if a line is parallel to the one side of a triangle then that the line intersects the other two sides of the triangle in the same ratio.
Using Basic proportionality theorem, we get
Adding x on both sides, we get
The missing length is 3 Therefore, the correct option is D.