K is the slope of the line formed by connecting the points.
Use slope formula:

where the 2 points are the end points of the line (First and last going Left to right)

Substitute into slope formula

You can check if this is correct by going back to graph and going "up 7" and "over 2" to get from one point to the next.
H=(√3)*a/2 = 41.2
So, a=2*41.2/√3=47.6
Answer:
1) 2/7; 43; 3/7
2) C
3) 30; 30; 10; is not; 10; is not
Step-by-step explanation:
1) y + 4/7 = 6/7
y = 6/7 - 4/7
y = 2/7
17 + b = 60
b = 60 - 17
b = 43
6/7 = m + 3/7
m = 6/7 - 3/7
m = 3/7
2) 11.5 - x = 5.25
x = 11.5 - 5.25
x = 6.25
3) he can substitute 30 for t.
He can then multiply ⅓ by 30 to get a product of 10 (⅓ × 30 = 10).
Since 15 is not equal to 10, Harry's solution is not correct