Answer:
Perimeter is 17.07
Step-by-step explanation:
We know that DF = EF = 5 cm, since D and E are the midpoints of AC and AB, both of which are 10 cm in length.
We need to use the Pythagorean theorem to get the length of DE.

So the perimeter of DEF is 5 + 5 + 7.07 = 17.07
Answer:
1.8 units.
Step-by-step explanation:
The questions which involve calculating the angles and the sides of a triangle either require the sine rule or the cosine rule. In this question, the two sides that are given are adjacent to each other and the given angle is the included angle. This means that the angle is formed by the intersection of the two lines. Therefore, cosine rule will be used to calculate the length of the largest side of the triangle. The cosine rule is:
b^2 = a^2 + c^2 - 2*a*c*cos(B).
The question specifies that a=0.5, B=120°, and c=1.5. Plugging in the values:
b^2 = 0.5^2 + 1.5^2 - 2(0.5)(1.5)*cos(120°).
Simplifying gives:
b^2 = 3.25.
Taking square root on the both sides gives b = 1.8 (rounded to the nearest tenth).
This means that the length of the third side is 1.8 units!!!
Step-by-step explanation:
I got this much.....
I am sorry of it gets wrong
You should search it on youtube becouse pepople cant really explain or draw the shape to show you