You need this key result: in any polygon, the sum of the interior angles is

where
is the number of sides of the polygon.
Your polygon has seven sides, and the measures of all angles are given. So, we can write

Again, we've simply written that the sum of all interior angles is the number of sides, minus two, times 180.
We can simplify both sides: we sum like terms on the left hand side, and we easily compute the right hand side:

and we can solve this equation for
by dividing both sides by 30:

Finally, the required angles is 
First you need to know how many pounds of carbon dioxide you get when burning 1 gallon of gasoline. That number is 19.64 pounds
To get the number of pounds released when entire tank is burned you need to multiply gas tank volume and number of pounds you get when 1 gallon is burned.
17.2 * 19.64 = 337.808
Red blood cell, as they have a biconcave shape and need to store a lot of haemoglobin, the pigment of blood
hope this helps! :)
118.73 that's the answer, you have to use long multiplication. Hope I helped