express the equation of x/a + y/b =1 to the form of xcosA +ysinA= p and prove that 1/a^2 +1/b^2 =1/p^2.​

Aphoto of a painting measured 13 x 17 inches the scale of the photo to the original painting is 1 inch to 3 inches. what is the size of this painting

What is the length of the missing leg in this right triangle? 18 mm 24 mm 26 mm 32 mm

Ineed if you could explain and give me the answer you! this needs done