Answer:
80°
Step-by-step explanation:
Let the angle be x then four times it's complement plus 60, that is
4(90 - x) + 60 ← is it's supplement
Supplementary angles sum to 180°
Sum the angle and it's supplement and equate to 180
x + 4(90 - x) + 60 = 180 ← distribute and simplify left side
x + 360 - 4x + 60 = 180
- 3x + 420 = 180 ( subtract 420 from both sides )
- 3x = - 240 ( divide both sides by - 3 )
x = 80
The required angle = x = 80°
supplement = 4(90 - 80) + 60 = 4 × 10 + 60 = 40 + 60 = 100°
Answer: 
Step-by-step explanation:
To find the least common multiply, you must descompose 12 and 15 into their prime factors, as you can see below:
12=2*2*3=2²*3
15=3*5
Choose the common and non common numbers with their greastest exponents:
3*5*2²=60
Now you must choose the common and non common variables with their greastest exponents:
n³
Therefore, you can conclude that the least common multiply is:

Gh is a half of DF because it is a midline
2(3x-4)=9x-59
6x-8=9x-59
3x=51
X=17