Negatives and Square Roots = 17 Find Ask yourself? ‘What number, times itself, equals 289? Since (17)(17) = 289, the square root of 289 is 17... – Find = –17 (–17) (–17) = 289 ... but, there’s another number, times itself, that also equals 289. When the negative is outside the radical, your answer is negative. – Find = undefined (not possible) You cannot find the square root of a negative number. There’s no number, times itself, that equals a negative number. When the negative is inside the radical, your answer is undefined.
Estimating Square Roots ≈ 18 Find Ask yourself? ‘What number, times itself, equals 340 ? nothing Since 340 isn’t a perfect square, what perfect squares are near 340 ? 18 = 19 = 340 Since is a little closer to , the square root of 340 is approximately 18. Find – ≈ –18 –19 = – 18 =