Answer:
d = 10/72
Step-by-step explanation:
c and d vary inversely
c = k/d
Where,
k = constant of proportionality
d = 2/9 when c = 5
c = k/d
5 = k ÷ 2/9
5 = k × 9/2
5 = 9k/2
Cross product
5*2 = 9k
10 = 9k
k = 10/9
c = k/d
c = 10/9 ÷ d
c = 10/9 × 1/d
c = 10/9d
find d when c = 8
c = 10/9d
8 = 10/9d
Cross product
8*9d = 10
72d = 10
d = 10/72
The original side length was 12m therefore the perimeter was 36m. 12/4 is 3 so the perimeter is now 9, and the difference between them is 27.
Answer:
1. 8/$12=21/$x then cross multiply.
2. 1/$1.5, we're looking for cost so $1 is more reasonable
3. $31.5
Step-by-step explanation:
12x 21/ 8 = 31.5
Here are the 4 inequality signs.

---> a is less than b

---> a is less than or equal to b

---> a is greater than b

---> a is greater than or equal to b
For the second and fourth lines above, the two sides may or may not be equal.
For the first and third lines above, the two sides cannot be equal.