The definition of a rhombus is that it's a polygon with four congruent sides. If you split one into two pieces with a diagonal, then yes, it will be two isosceles triangles because two sides are congruent.

so.... since the number after .81 is 1, it doesn't really round up to .82, so is just that, 15.81.
Answer:
second
Step-by-step explanation:

Answer:
-13 
Step-by-step explanation:
To multiply fractions with both the fraction and whole number you must convert it to an improper fraction by multiplying the whole numbers by the denominators, which you would get 35 for the first fraction and -10 for the second, then you must add the numerators to that number and put the number into the numerator spot. at this point you should have
and
.
Now, multiply the numerators by the numerators and the denominators by the denominator and keep it aligned so the products stay in fraction form. now you should have
.
Divide the numerator by the denominator to get the whole number, in this problem that comes out to 13. The remainder of this division becomes the new numerator which in this case would also be 13 and the denominator stays the same so now you have -13
which is the answer
Hope i helped!