Which angle is adjacent to 9 ?

Timed*** there are 8 rows and 8 columns, or 64 squares on a chessboard. suppose you place 1 penny on row 1 column a, 2 pennies on row 1 column b, 4 pennies on row 1 column c, and so on … how many pennies are on each square? a =   b =   c = d =   e =   f = g =   h =

How many solutions does the nonlinear system of equations graphed below have?

In need of in the diagram, ∠abc is a right angle. ∠dbc = 30°27'40". find the measure of ∠abd.