Answer:
I think the right answer would be 7
Step-by-step explanation:
We got-ta use the equation: CA * BA = DA²
CA = 15 + BA
DA² = 8² = 64
=> (15 + BA) BA = 64
Subtract 15 from each side:
BA(BA) = 49
BA² = 49
Now take the square root of each side
BA = 7
Hope this helps!
Answer:



Step-by-step explanation:
Given
Let the three sides be represented with A, B, C
Let the angles be represented with 
[See Attachment for Triangle]



What the question is to calculate the third length (Side B) and the other 2 angles (
)
Solving for Side B;
When two angles of a triangle are known, the third side is calculated as thus;

Substitute:
,
; 




Take Square root of both sides



<em>(Approximated)</em>
Calculating Angle 

Substitute:
,
; 




Subtract 180 from both sides


Divide both sides by -144



Take arccos of both sides



<em>(Approximated)</em>
Calculating 
Sum of angles in a triangle = 180
Hence;



Make
the subject of formula


First you must know that for remarkable angles: cos (0) = 1, cos (π) = - 1, cos (π / 2) = 0, cos (3π / 2) = 0, cos (2π) = 1. Then, by simple substitution in the given formula, you can find the solutions of x. Which for the interval [0, 2π) are: x = π, x = pi divided by two and x = three pi divided by two.Attached solution.