# Tutor profile: John D.

## Questions

### Subject: Pre-Calculus

Marlon opened a savings account and deposited $200.00 as principal. The account earns 7% interest, compounded continuously. What is the balance after 4 years?

P= 200 r= 0.07 t= 4 A=Pe^(rt) A= 264.63

### Subject: Trigonometry

A nursery plants a new tree and attaches a guy wire to help support the tree while its roots take hold. An eight foot wire is attached to the tree and to a stake in the ground. From the stake in the ground the angle of elevation of the connection with the tree is 42º. Find to the nearest tenth of a foot, the height of the connection point on the tree.

This problem deals with "opposite" and "hypotenuse" making it a sine problem. sin(42 degrees)= x/8 .669 = x/8 x= 5.4'

### Subject: Geometry

A circle has an area of 49pi square units. What is the length of the circle's diameter?

The formula for the area A of a circle with radius r is: A = (pi)r2 I know that radius r is half of the length of the diameter d, so: 49pi = (pi)r2 (49pi) / pi = [(pi)r2] / pi 49 = r2 7 = r Then the radius r has a length of 7 units, and: the length of the diameter is 14 units

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