L= 1/2 (4+12) 1/2 (3a)

Lisa has three classes that each last 50 minutes. what is the total number of minutes of the three classes

Find and simplify an expression for the area of five rows of x squares with side lengths of x centimeters.

Kayla wants to find the width, ab, of a river. she walks along the edge of the river 65 ft and marks point c. then she walks 25 ft further and marks point d. she turns 90° and walks until her location, point a, and point c are collinear. she marks point e at this location, as shown. (a) can kayla conclude that δ and δ are similar? why or why not? (b) suppose de = 15 ft. what can kayla conclude about the width of the river?