Can you try rewording this question?
Given:
In a right angle triangle θ is an acute angle and
.
To find:
The value of
.
Solution:
In a right angle triangle,

We have,

It means the ratio of perpendicular to base is 3:5. Let 3x be the perpendicular and 5x be the base.
By using Pythagoras theorem,





In a right angle triangle,



Therefore, the value of
is
.
Area of a triangle is equal to 1/2 b(h) so since you already have the height and base, all you need to do is input it back into the equation:

(10)(13)
Multiply 10 & 13 to equal

(130)
Then take half of 130 to get
A = 65
Is there supposed to be a picture here?? There isn’t.