I’m not sure what I have doing wrong but it still incorrect

Answer:
280.2 m²
Step-by-step explanation:
The height of the triangle is found using the Pythagorean theorem.
a² +b² = c²
13² +b² = 20²
b² = 20² -13² = 400 -169 = 231
b = √231 ≈ 15.199 . . . . meters
The area of the figure is 1/4 the area of a circle with radius √231 together with the area of the triangle with base 13 and height √231.
Triangle Area = 1/2bh
= 1/2(13)(15.199) ≈ 98.791 . . . . square meters
__
The area of the 1/4 circle is ...
Sector Area = (1/4)πr² = 1/4π(√231)² = (231π)/4 ≈ 181.427 . . . . square meters
__
The figure area is the sum of the triangle and quarter circle areas:
figure area = 98.791 m² +181.427 m² ≈ 280.2 m²
_____
Additional comment
If you use 3.14 for π, then the total will be 280.1 m².
Answer:
280.2 sq meters
Step-by-step explanation:
First you have to find the third side of the triangle because it is the height of the triangle and also the radius of the circle. Using Pythagorean theorem:
x^2 + 13^2 = 20^2
x^2 + 169 = 400
x^2 = 400 - 169
x^2 = 231
x = sqroot(231)
x = 15.2
Area of triangle:
A = 1/2 b•h
= 1/2•13•15.2
= 98.8
Area of a circle:
A = pi•r^2
Area of a 1/4 Circle:
A = 1/4•pi•r^2
=1/4(3.14)(15.2)^2
= 181.4
Area of Whole Shape:
98.8 + 181.4
= 280.2 sq meter