Answer:
8.) <u> C = 129.341°</u>
9.) <u> </u><u>C = 90°</u>
10.) <u> </u><u>C = 90°</u>
Step-by-step explanation:
<u>For part 8.</u>
given A=50°, a=15, b=12
In any triangle, the ratio of side length of to the sine of its opposite angle
is the same for all three sides:
![\frac{a}{SinA}=\frac{b}{SinB}=\frac{c}{SinC}](https://tex.z-dn.net/?f=%5Cfrac%7Ba%7D%7BSinA%7D%3D%5Cfrac%7Bb%7D%7BSinB%7D%3D%5Cfrac%7Bc%7D%7BSinC%7D)
Now put the value of A=50°, a=15, b=12 in above formula
![\frac{15}{Sin50}=\frac{12}{SinB}](https://tex.z-dn.net/?f=%5Cfrac%7B15%7D%7BSin50%7D%3D%5Cfrac%7B12%7D%7BSinB%7D)
Since, the value of Sin50°=0.766
![\frac{15}{0.766}=\frac{12}{SinB}](https://tex.z-dn.net/?f=%5Cfrac%7B15%7D%7B0.766%7D%3D%5Cfrac%7B12%7D%7BSinB%7D)
![\frac{15}{0.766}=\frac{12}{SinB}](https://tex.z-dn.net/?f=%5Cfrac%7B15%7D%7B0.766%7D%3D%5Cfrac%7B12%7D%7BSinB%7D)
![19.58=\frac{12}{SinB}](https://tex.z-dn.net/?f=19.58%3D%5Cfrac%7B12%7D%7BSinB%7D)
simplify the above,
![SinB=\frac{12}{19.58}](https://tex.z-dn.net/?f=SinB%3D%5Cfrac%7B12%7D%7B19.58%7D)
![SinB=0.6128](https://tex.z-dn.net/?f=SinB%3D0.6128)
take inv sin both the sides,
![B=0.659\,\text{degree}](https://tex.z-dn.net/?f=B%3D0.659%5C%2C%5Ctext%7Bdegree%7D)
since some of angles of triangle is 180
so,
A + B + C = 180°
50 + 0.659 + C = 180°
50.659 + C = 180°
subtract 50.659 from both the sides,
C = 180°-50.659
<u> C = 129.341°</u>
<u>For part 9</u>
given A=50°, a=10, b=15
Since, ![\frac{a}{SinA}=\frac{b}{SinB}=\frac{c}{SinC}](https://tex.z-dn.net/?f=%5Cfrac%7Ba%7D%7BSinA%7D%3D%5Cfrac%7Bb%7D%7BSinB%7D%3D%5Cfrac%7Bc%7D%7BSinC%7D)
Now put the value of A=50°, a=10, b=15 in above formula
![\frac{10}{Sin50}=\frac{15}{SinB}](https://tex.z-dn.net/?f=%5Cfrac%7B10%7D%7BSin50%7D%3D%5Cfrac%7B15%7D%7BSinB%7D)
Since, the value of Sin50°=0.766
![\frac{10}{0.766}=\frac{15}{SinB}](https://tex.z-dn.net/?f=%5Cfrac%7B10%7D%7B0.766%7D%3D%5Cfrac%7B15%7D%7BSinB%7D)
![13.0548=\frac{15}{SinB}](https://tex.z-dn.net/?f=13.0548%3D%5Cfrac%7B15%7D%7BSinB%7D)
simplify the above,
![SinB=\frac{15}{13.0548}](https://tex.z-dn.net/?f=SinB%3D%5Cfrac%7B15%7D%7B13.0548%7D)
![SinB=1.149](https://tex.z-dn.net/?f=SinB%3D1.149)
take inv sin both the sides,
![B=40\,\text{degree}](https://tex.z-dn.net/?f=B%3D40%5C%2C%5Ctext%7Bdegree%7D)
since some of angles of triangle is 180
so,
A + B + C = 180°
50° + 40° + C = 180°
90° + C = 180°
subtract 90 from both the sides,
C = 180°-90°
<u> </u><u>C = 90°</u>
<u>For Part 10</u>
given A=47°, a=1.5, b=2
Since, ![\frac{a}{SinA}=\frac{b}{SinB}=\frac{c}{SinC}](https://tex.z-dn.net/?f=%5Cfrac%7Ba%7D%7BSinA%7D%3D%5Cfrac%7Bb%7D%7BSinB%7D%3D%5Cfrac%7Bc%7D%7BSinC%7D)
Now put the value of A=47°, a=1.5, b=2 in above formula
![\frac{1.5}{Sin47}=\frac{2}{SinB}](https://tex.z-dn.net/?f=%5Cfrac%7B1.5%7D%7BSin47%7D%3D%5Cfrac%7B2%7D%7BSinB%7D)
Since, the value of Sin47°=0.123
![\frac{1.5}{0.123}=\frac{2}{SinB}](https://tex.z-dn.net/?f=%5Cfrac%7B1.5%7D%7B0.123%7D%3D%5Cfrac%7B2%7D%7BSinB%7D)
![12.195=\frac{2}{SinB}](https://tex.z-dn.net/?f=12.195%3D%5Cfrac%7B2%7D%7BSinB%7D)
simplify the above,
![SinB=\frac{15}{12.195}](https://tex.z-dn.net/?f=SinB%3D%5Cfrac%7B15%7D%7B12.195%7D)
![SinB=1.23](https://tex.z-dn.net/?f=SinB%3D1.23)
take inv sin both the sides,
![B=43\,\text{degree}](https://tex.z-dn.net/?f=B%3D43%5C%2C%5Ctext%7Bdegree%7D)
since some of angles of triangle is 180
so,
A + B + C = 180°
47° + 43° + C = 180°
90° + C = 180°
subtract 90 from both the sides,
C = 180°-90°
<u> </u><u>C = 90°</u>