A triangle has two corners with angles of pi / 2 π2 and ( pi )/ 8 π8. If one side of the triangle has a length of 3 3, what is the largest possible area of the triangle?

1 Answer
Feb 27, 2018

Largest possible area of the triangle is

A_t = color(indigo)(10.864At=10.864 sq units

Explanation:

hat A = pi/2, hat B = pi/8ˆA=π2,ˆB=π8

Third angle hat C = pi - pi / 8 /- pi /2 = (3pi)/8ˆC=ππ8/π2=3π8

To get largest area, side with length 3 should correspond to the smallest angle pi/8π8

Applying law of sines,

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3 / sin (pi/8) = b / sin (pi/2) = c / sin (3pi)/83sin(π8)=bsin(π2)=csin(3π)/8

b = (3 * sin (pi/2)) / sin (pi/8) = 7.8394b=3sin(π2)sin(π8)=7.8394

Area of the tan be arrived at by using the formula

A_t = (1/2) a b sin C = (1/2) * 3 * 7.8394 * sin ((3pi)/8) = 10.864At=(12)absinC=(12)37.8394sin(3π8)=10.864 sq units.

Alternatively,

c = (3 * sin ((3pi)/8)) / sin (pi / 8) = 7.2426c=3sin(3π8)sin(π8)=7.2426

Since it’s a right triangle,

enter image source here

A_t = (1/2) a c = (1/2) 3 * 7.2426 = 10.864At=(12)ac=(12)37.2426=10.864