Steve and his daughter went on 30- mile backpacking trek in yosemite national park. they hiked 7.7 mi the first day , 6.4 the second day and 8.0 mi the third day. how much farther did they have to go ?

To answer this question you basically have to add up day 1, day 2 and day three then take it away from 30 so

7.7+6.4+8.0=22.1

30-22.1=7.9 so they have 7.9 miles left to walk

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.

it's both, now can you answer my most recent question?