Answer:
a. 
b. 0.7
c. 0.7=70%=
Step-by-step explanation:
70% of 100 received an A, that is 70/100 times 100 equal to 70

a. 70% = 
b.
= 0.7
Notice that 70/100 is equal to 7/10 which is 0.7
c. 0.7=70%=
Multiple and add
Step-by-step explanation:
For all of them you multiple 1 and add the inherent that's what area and perimter means
BD = BA + AD
51 = 26 + AD
-26 on both sides
AD = 25