advertisement

ESTIMATING Square Roots Vocabulary Square Root: will be a positive and negative value o When written in words “what is the square root of 36” write as +6 and -6 Principal Square Root- is used with the √49 - only give positive value (+7) Negative square root = -√49 = -7 (notice the negative sign is outside of the√ sign! What is the square root of 20? (√20) Find the perfect squares before and after the √20 √ 16 4 < √20 < √25 < √20 < 5 List the square roots from 16 to 25 (number line) √16 √17 √18 √19 √20 √21 √22 √23 √24 √ 25 4 4.5 5 Find the middle value (like you do with median) Is the estimated square root before or after the middle value? √20≈4.45 The estimated value of √20 is before the 4.5 The √20 is very close to the 4.5. My estimate is 4.45 or 4.4 Estimate the √108 √100√101√102√103√104√105√106√107√108√109√110√111√112√113√114√115√116√117√118√119√120√121 10 10.25 10.37 10.4 10.5 First I found the middle The √108 is before the middle point (10.5) Then I found the middle of the lower half (10.25) Then I found the middle point between the 10.25 and 10.5 (10.37) √108 is really close to 10.37. It must be 10.4 To show your work, 1.) 2.) 3.) 4.) √ 100 <√ 108 < √121 10 < √108 <11 Number line work - find the median then estimate √108 ≈ 10.4 10.75 11