



 
Mitchell, I redrew the diagram that you sent. Write the equation of the line through AD, 3x + 4y  60 = 0, in the form y = mx + b. I got
Thus the slope of this line is 3/4. Since ABCD is a rectangle CD is perpendicular to AD and thus its slope is the negative reciprocal of 3/4, that is 4/3. Write the equation of the line through (18, 14) with slope 4/3. Solve this equation with equation (*) to find the coordinates of D. Find the distance between C and D. Since you know the perimeter is 52 cm you can now find the length of the segment AD. Penny  


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