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

  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

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The area of the 1/4 circle is ...

  Sector Area = (1/4)πr² = 1/4π(√231)² = (231π)/4 ≈ 181.427 . . . . square meters

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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.

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

51

step-by-step explanation:

73-22=51 the   mass number minus the amount of protons gives you the amount of neutrons

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