Answer:check explanation below
Step-by-step explanation:
Okay so for Part A: since B is the midpoint of SM, SM=SB+BM. Therefore, you can set them both equal to each other which would be 4x=98.3. You divide both sides by 4 to get the value of x which is 24.575. Now you substitute 24.575 back into 4x and you get 98.3. Since SM=SB+BM, you do 98.3+98.3 and SM=196.6.
Part B: For part b you do the same thing as A to find the values of x y and x. You already know that x=24.575. For Y, since T is the midpoint of DS you can set ST=TD. This means that 123.4=2/5y. When you solve for y you get y=308.5. Lastly, for z since N is the midpoint of MD, MN=ND. So 102=7/10z. When you solve for z you get approximately 145.7. Now you just add them together -- 24.575+308.5+145.7= 478.775.
Part C: NT is half of SM. Since SM is 196.6, NT is 98.3. TB is half of MD. MD is 203.99 so TB is 101.995. BN is half of SD. SD is 246.8 so BN is 123.4
So, NT+TB-BN is 98.3+101.995-123.4 which equals 76.895
