In triangle abc , side bc is 3 inches long and side ab is 16 inches long. angle a measures 20 °. given that angle c is an obtuse angle, find the measure of angle c. round to the nearest tenth of a degree

Angle C is 101 degrees

Step-by-step explanation:

Given triangle ABC,

Side BC =3

Side AB =16

Angle A=20

Also, Angle C is an obtuse angle.

To find Angle C:

As shown in figure,

By using basic trigonometry,

Angle A =20 and AB=13

BD =13sin20 and AD = 13cos20

Now, AD=AC+CD

CD=13cos20-3

CD=2.30506

And BD =13sin20=11.86828

In triangle BDC,

Tan(BCD) =

Tan(BCD) =

Tan(BCD) = =5.1487

Angle BCD = 79.00

Therefore, Angle BCA =180-Angle BCD=180-79=101.

Angle C is 101 degrees

(b) 240

step-by-step explanation:

first, we use the pythagorean formula using the given side lengths to find x. then we use x to find the side lengths. then we add the side lengths to find the perimeter.

pythagorean theorem formula:

a^2 + b^2 = c^2

(x - 20)^2 + (x - 40)^2 = x^2

x^2 - 40x + 400 + x^2 - 80x + 1600 = x^2

x^2 -120x + 2000 = 0

(x - 100)(x - 20) = 0

x - 100 = 0 or x - 20 = 0

x = 100 or x = 20

we see that the solution x = 20 must be discarded because it will give a negative side length and a side length of 0. the only valid solution is x = 100.

perimeter = sum of the lengths of the sides

perimeter = x + x - 20 + x - 40

perimeter = 3x - 60

replace x with 100.

perimeter = 3(100) - 60

perimeter = 300 - 60

perimeter = 240