Answer:
The measure of angle RST is 
Step-by-step explanation:
see the attached figure to better understand the problem
we know that
-----> equation A
-----> equation B
equate equation A and equation B




The measure of angle RST is equal to

Answer:
A)10.25 cm ; B)5 square cm
Step-by-step explanation:
A)
Formula:
p=(a+b+c) [p= perimeter ; a,b , and c are the side lengths.]
∴The perimeter of the triangle =(4+2.75+3.5) cm
=10.25 cm
B)
Formula:
A = 1/2 . b .h [A=area ; b= base ; h= height]
∴The area of the triangle = (1/2 . 4 . 2.5) square cm [b=4 ; h=2.5]
=5 square cm
All you have to do is combine like terms. 2c and (-c) are like terms (-5b) and (-b) are like terms and a is a term. So, 2c combined with (-c) is C. (-5b) and (-b) combined is (-6b). Since a doesnt need to be combined with anything, you leave it as it is so your answer will then be c - 6b + a (this is the answer assuming that there is a + in front of the a. If there is a - sign, then just change your +a to -a at the end