The perimeter of a triangle is 27 inches. only 2 sides are known 12.3 and 5.4. what is the third side and what is the equation

Can someone me with my hwplz(only the circled ones)

What is 140% of 25? because i need

Worth 100 points need the answers asap first row -x^2 2x^2 (x/2)^2 x^2 x is less than 2 x is greater than 2 x is less than or equal to 2 x is greater than or equal to 2 second row -5 -5/2 4 5 •2 is less than x& x is less than 4 •2 is less than or equal to x & x is less than or equal to 4 •2 is less than or equal to x& x is less than 4 •2 is less than x& x is less than or equal to 4