Answer:
perimeter of ΔDEF ≈ 32
Step-by-step explanation:
To find the perimeter of the triangle, we will follow the steps below:
First, we will find the length of the side of the triangle DE and FF
To find the length DE, we will use the sine rule
[tex]\frac{sin E}{e} = \frac{sin F}{f}[/tex]
angle E = 49 degrees
e= DF = 10
angle F = 42 degrees
f= DE =?
we can now insert the values into the formula
[tex]\frac{sin 49}{10}[/tex] = [tex]\frac{sin 42}{f}[/tex]
cross-multiply
f sin 49° = 10 sin 42°
Divide both-side by sin 49°
f = 10 sin 42° / sin 49°
f≈8.866
which implies DE ≈8.866
We will now proceed to find side EF
To do that we need to find angle D
angle D + angle E + angle F = 180° (sum of interior angle)
angle D + 49° + 42° = 180°
angle D + 91° = 180°
angle D= 180° - 91°
angle D = 89°
Using the sine rule to find the side EF
[tex]\frac{sin E}{e} = \frac{sin D}{d}[/tex]
angle E = 49 degrees
e= DF = 10
ange D = 89 degrees
d= EF = ?
we can now proceed to insert the values into the formula
[tex]\frac{sin 49}{10}[/tex] = [tex]\frac{sin 89}{d}[/tex]
cross-multiply
d sin 49° = 10 sin 89°
divide both-side of the equation by sin 49°
d= 10 sin 89°/sin 49°
d≈13.248
This implies that length EF = 13.248
perimeter of ΔDEF = length DE + length EF + length DF
=13.248 + 8.866 + 10
=32.144
≈ 32 to the nearest whole number
perimeter of ΔDEF ≈ 32
