Chris's backyard is in the shape of a trapezoid the bases are 30 and 40 feet long the height is 15 ft find the area of chris's back yard

I have n idea good luck tho

the law of definite proportions states samples of a compound will always contain the same proportion of elements by mass. in other words, a given compound will always contain the same elements in the same proportions by mass.the law of multiple proportions states when two elements combine with each other to form more than one compound, then the weights of one element that combine with a fixed weight of the other are in a ratio of small whole numbers.