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Square roots
Square roots of perfect squares
Positive and negative square roots
Estimate positive and negative square roots
Relationship between squares and square roots
Evaluate expressions involving squares and square roots
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Estimate positive and negative square roots
You can estimate the square roots of numbers that are not perfect squares.
Estimating Square Roots
To estimate the square roots of r, find perfect squares on each side of r. Use these to estimate.
a.
Estimate
to the nearest whole number
b.
Estimate
to the nearest whole number
Find a perfect square a little less than 38 and one a little more than 38.
, so
.
Since 38 is closer to 36 than 49, the best whole number estimate for
is 6.
Find a perfect square a little less than 21.6 and one a little more than 21.6.
, so
.
Since 21.6 is closer to 25 than 16, the best whole number estimate for
is 5.
a.
Estimate
to the nearest whole number
b.
Estimate
to the nearest whole number
Find a perfect square a little less than 32 and one a little more than 32.
, so
.
Since 32 is closer to 36 than 25, the best whole number estimate for
is -6.
Find a perfect square a little less than 18 and one a little more than 18.
, so
.
Since 18 is closer to 16 than 25, the best whole number estimate for
is -4.