Evaluating Expressions

Evaluating Expressions

L10.2 page 273

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11. The area of a triangular sail is given by the expression $\frac{1}{2}$ bh, where b is the length of the base and h is the height. What is the area of a triangular sail in a model sailboat when b = 12 inches and h = 7 inches?

A =

  $in^2$  

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12. Ramon wants to balance his checking account. He has $2,340 in the account. He writes a check for $140. He deposits a check for $268. How much does Ramon have left in his checking account?

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14. The kinetic energy (in joules) of a moving object can be calculated from the expression $\frac{1}{2}$  $mv^2$  , where m is the mass of the object in kilograms and v is its speed in meters per second. Find the kinetic energy of a 0.145-kg baseball that is thrown at a speed of 40 meters per second. 

E =

joules

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15. The area of a square is given by $x^2$ , where x is the length of one side. Mary’s original garden was in the shape of a square. She has decided to double the area of her garden. Write an expression that represents the area of Mary’s new garden. Evaluate the expression if the side length of Mary’s original garden was 8 feet. 

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16. The volume of a pyramid with a square base is given by the expression  $\frac{1}{3}s^2h$  , where s is the length of a side of the base and h is the height. Find the volume of a pyramid with a square base of side length 24 feet and a height of 30 feet.
V=

  $ft^2$  

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Melinda is hauling water in her pickup truck. An old bridge has a

maximum weight limit of 6,000 pounds. To find the weight of her truck,

Melinda uses the expression 5,275 + 8.36g, where g is the number of

gallons of water she is hauling. Can Melinda safely drive her pickup

across the bridge if she is hauling 120 gallons of water? Explain.

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A certain machine produces parts that are rectangular prisms. The surface area of each part is found by using the expression $2s^2+4sh$ , where s is the length of a side of the base and h is the height. What is the surface area of that part when s is 0.5 mm and h is 2 mm? 

  $mm^2$