It is b lol
That is the answer
Answer:
3.7
Step-by-step explanation:
To change a fraction to a decimal, just divide the numerator with the denominator. Instead of placing the remainder over the divisor, continue to solve until it is answered (unless it's a repeating decimal.)
Divide 7 with 10:
7/10 = 0.7
Remember that there is a whole number, 3. Add that to the decimal you have gotten:
3 + 0.7 = 3.7
3.7 is your answer.
~
3x + 4x +5x = 54 (because the perimeter = sum of its dies)
12x = 54
x = 4.5
So the 3 sides are 3*4.5 , 4*4.5 and 5*4.5
= 13.5, 18 and 22.5 units (answer)
If it's a regular octahedron, then you can calculate it using the formula

where

is the length of the edge.
If it's not regular, you have to calculate the area of each side individually.