Day 12 - Solve Using Square Roots

Evaluate: 64 1 100 49 144

With your calculator: 33 = _____________ 54 = _____________

(round to the nearest hundredth)

Think about it: What number can you plug into each of these equations to make them true:

1) x2 = 9 2) x2 = 25 3) x2 = 121

Remember: ___________________________________________________________________________________________________

4) 2x2 = 8 5) 2x2 + 3 = 35 6) 3x2 + 4 = 112

Some different cases. Solve with your partner, and discuss what you see.

7) x2 – 18 = -18 8) x2 +12 = 3

Please take out your calculator! (These types of problems won’t always be perfect squares…) Solve: 9) x2 – 7 = 4 10) 4x2 + 10 = 11 11) 4x2 – 38 = 0

You Try with your Partner:

1. x2 + 24 = 60 2) 4x2 – 100 = -100 3) x2 + 20 = 18

Application Word Problems

1. You have a square quilt that your Great Grandma gave you which has an area of 1600 square

inches. What is the length of one side?

2. A pen drops from the top of a desk that is 6 feet tall. The distance from the pen to the ground can

be modeled by the equation h = -16t2 + s, where h is the final height, t is the time in seconds, and s

is the initial height from the ground in feet. How long will it take for the pen to reach the ground?

Round your answer to the nearest tenth of a second

3. The velocity (in meters per second) of a car speeding up based on time can be modeled by the equation

5v t , where t is the time for speeding up the car in second. How long does it take for the car to go

20 meters per second?