91Ó°ÊÓ

Bequests to charity: At the time our mother left this Earth, she gave \(\$ 9000\) to her children of birth. This we kept and each year added \(\$ 3000\) more, as a lasting memorial from the children she bore. When \(\$ 42,000\) is thusly attained, all goes to charity that her memory be maintained. What was the balance in the sixth year? In what year was the goal of \(\$ 42,000\) met?

From elementary geometry it is known that the interior angles of a triangle sum to \(180^{\circ},\) the interior angles of a quadrilateral sum to \(360^{\circ}\) the interior angles of a pentagon sum to \(540^{\circ},\) and so on. Use the pattern created by the relationship between the number of sides to the number of angles to develop a formula for the sum of the interior angles of an \(n\) -sided polygon. The interior angles of a decagon ( 10 sides) sum to how many degrees?

In the game of "Twister" (Milton Bradley) a simple spinner is divided into four quadrants designated Left Foot (LF), Right Hand (RH), Right Foot (RF), and Left Hand (LH), with four different color possibilities in each quadrant (red, green, yellow, blue). Determine the number of possible outcomes for three spins.

Pendulum movement: On each swing, a pendulum travels only 80% as far as it did on the previous swing. If the first swing is 24 ft, how far does the pendulum travel on the 7th swing? What total distance is traveled before the pendulum comes to rest?

Find a unit vector in the same direction as \(3 i-7 j.\)