# Word problems on linear and quadratic equations

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114. Diameter of a circle. If the diameter of a circle is

1.3 x10^-12 meters, then what is its radius?

94. Perimeter of a rectangle. The width of a rectangular playground

is 2x x- 5 feet, and the length is 3x + 9 feet. Write a

polynomial P(x) that represents the perimeter and then

evaluate this perimeter polynomial if x is 4 feet.

98. Height difference. A red ball and a green ball are

simultaneously tossed into the air. The red ball is given an

initial velocity of 96 feet per second, and its height t seconds

after it is tossed is -16t^2 + 96t feet. The green ball

is given an initial velocity of 80 feet per second, and its

height t seconds after it is tossed is -16t^2 + 80t feet.

a) Find a polynomial D(t) that represents the difference in

the heights of the two balls.

b) How much higher is the red ball 2 seconds after the

balls are tossed?

c) In reality, when does the difference in the heights stop

increasing?

79. Area. A roof truss is in the shape of a triangle with height

of x feet and a base of 2x +1 feet. Write a polynomial A(x)

that represents the area of the triangle.

86. Selling shirts. If a vendor charges p dollars each for

rugby shirts, then he expects to sell 2000 - 100p shirts at

a tournament.

98. Area of a parallelogram. Find a trinomial A(x) that represents

the area of a parallelogram whose base is 3x + 2

meters and whose height is 2x + 3 meters.

96. Compounded semiannually. P dollars is invested at annual

interest rate r for 1 year. If the interest is compounded

semiannually, then the polynomial P (1+r/2)^2

represents the

value of the investment after 1 year. Rewrite this expression

without parentheses. Evaluate the polynomial if

P = $200 and r = 10%.

88. Perimeter of a rectangle. The perimeter of a rectangular

backyard is 6x + 6 yards. If the width is x yards, find a

binomial that represents the length.

#### Solution Summary

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