Pls answer this and explain!

Well if you add up all 3 angles in a triangle you’d get 180 degrees as the answer.

So we can. Jus substitute.

For number 19 you can do this

57+x+x+87+50=180

Now combine like terms

194+2x=180

Now solve

x=-7

Now we can subsitute that into angle A

57+ (-7) which is 50

Measure of angle A is 50.

For number 19 it’s the same thing.

9x+14+16x-4+80=180

Now combine like terms

25x+90=180

Solve

25x= 90

x= 3.6

Now subsitue for A

3.6*9+4 which is 36.4

A is 36.4

c.   x=2.4cm

step-by-step explanation:

similar triangles are triangles which have the same shape but not the same size. this means their angle measures are equal but their side lengths are not instead they are proportional. to solve, we will set up a proportion and solve.

a proportion is two equal ratios set equal to each other. we form the ratios by finding corresponding sides (sides which match to each other on both triangles by their position). out ratios will be one side of the small triangle over the corresponding side on the big triangle as shown below:

.

to solve the proportion, we'll cross multiply by multiplying numerator with denominator across the equal sign.