Answer:
The slope is 
Step-by-step explanation:
Let
and 
The slope is given by;

We plug in the values to get;

Simplify;


The angle m∠ABC is 70 degrees.
<h3>How to find angle in a rhombus?</h3>
The angle in a rhombus can be found as follows;
The opposite angle of a rhombus are congruent.
Therefore,
∠B = 140 degrees
Hence, the diagonal of a rhombus bisect an angle.
Therefore,
m∠ABC = 140 / 2
m∠ABC = 70 degrees.
learn more on rhombus here: brainly.com/question/11966028
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We will have to use the distance formula in order to determine the lengths of each side of the triangle.
Distance formula:

Let's calculate AB first:
A (1, 7) and B (-2, 2)
A: x1 = 1 and y1 = 7
B: x2 = -2 and y2 = 2
so



AB =

or (rounded to the nearest tenth) ≈ 5.8
Now let's do BC:
B: x1 = -2 and y1 = 2
C: x2 = 4 and y2 = 2
So


BC =

or 6
Now let's do CA
C: x1 = 4 and y1 = 2
A: x2 = 1 and y2 = 7
So



CA =

or (rounded to the nearest tenth) ≈ 5.8
So let's recap:
AB ≈ 5.8
BC = 6
CA ≈ 5.8
So AB and AC are the same length while BC is .2 units longer which means this is an
isosceles triangle.