Equilateral triangle means each angle equals 60 degrees.
60 = 7x - 3
63 = 7x
x = 9
Answer:

Step-by-step explanation:
we are given surface area and the length of the square base
we want to figure out the Volume
to do so
we need to figure out slant length first
recall the formula of surface area

where B stands for Base area
and P for Base Parimeter
so

now we need our algebraic skills to figure out s
simplify parentheses:

reduce fraction:

simplify multiplication:

cancel 64 from both sides;

divide both sides by 16:

now we'll use Pythagoras theorem to figure out height
according to the theorem

substitute the value of l and s:

simplify parentheses:

simplify squares:

cancel 16 from both sides:

square root both sides:

recall the formula of a square pyramid

where A stands for Base area (l²)
substitute the value of h and l:

simplify multiplication:

reduce fraction:

hence,

If you use a proportion, you'll get:

Then, you use cross products:

Then, you algebraically solve x:

The answer is 5/3 inches , or 1 5/13 inches, or 1.6 repeating.
a) 9/212 = #mph
b)0.000142045 Miles / 0.000277778 hours = # mph
Step-by-step explanation:
a) 9/212 = #mph
b)
1)9 inches divide the length value by 63360 is 0.000142045 Miles
2) 1 hour 3600 seconds in ones hour so 1/3600 =0.000277778
3) take miles/hour
0.000142045 Miles / 0.000277778 hours = # mph