Answer:
78° (to nearest degree)
*see step-by-step if higher degree of accuracy is needed*
Step-by-step explanation:
Area of a triangle = 1/2 x base x height
⇒ 143 = 1/2 x 11 x height
⇒ height = 26
Isosceles triangle comprises 2 right triangles, each with base 11/2 and height 26.
Therefore, to determine base angle use tan trig ratio:
[tex]\tan(\theta)=\dfrac{\textsf{opposite side}}{\textsf{adjacent side}}[/tex]
[tex]\implies tan(\theta)=\dfrac{26}{\frac{11}{2}}=\dfrac{52}{11}[/tex]
[tex]\implies tan(\theta)=78.05582281...[/tex]
