as you notice above, is the first-row components from A, multiplying all the columns subsequently on B, and you add the products of that row, that gives you one component on the AB matrix
in the one above, we end up with a 2x3 AB matrix
Solve for t in terms of y :
Substitute this into the parametric equation for x :
Hi! so what you want to do is first set up a proportion, if you know that the two triangles are congruent because abc~def you know that the proportion will work out. the proportion to set up is 54/72 from there you should know that 9 goes into both 72 and 54 so when you reduce you’d be left with 6/9 which you could further reduce to 2/3. then you can find the other sides by multiplying 92 by 2/3 and you’d get 61 and 84 by 2/3 where you’d get 56. However since you are supposed to find the perimeter, you would add all three sides together (54+56+61) and you’d be left with 171. hope this helps