The purity of gold is measured in? karats, with pure gold being 24 karats. other purities of gold are expressed as proportional parts of pure gold. thus? 18-karat gold is 18/24? , or? 75% pure? gold; 12-karat gold is 12/24? , or? 50% pure? gold; and so on. how much 16? -karat gold should be mixed with pure gold to obtain 80 grams of 20? -karat ? gold?

3. parallelogram

step-by-step explanation:

we turn each of our sides into direction vectors

ab=b-a=(3 - 7, 1 - 0) = (-4, 1)

bc=c-b=(1,6)

cd=d-c=(4,-1)

da=a-d=(-1,-6)

we see how the opposite sides have negated direction vectors; this is characteristic of a parallelogram.   we have congruent sides ab=cd and bc=da with unequal lengths because 1^2+6^2 is different from (-4)^2+1^2.   so it's not a square or a rhombus.  

we check the dot product of direction vectors of adjacent sides.   we have

ab dot bc = -4(1) + 1(6) = 2

that's not zero so the sides are not perpendicular.   we've ruled out rectangle.

the direction vectors indicate two pairs of congruent parallel sides, so we choose parallelogram over trapezoid.

25

step-by-step explanation:

correct

step-by-step explanation:

what is the question here

step-by-step explanation: