It is in the air 5.625 seconds.

Using the quadratic formula,

$t=\frac{-b\pm \sqrt{b^2-4ac}}{2a}
\\
\\=\frac{-90\pm \sqrt{90^2-4(-16)(0)}}{2(-16)}
\\
\\=\frac{-90\pm \sqrt{8100-0}}{-32}
\\
\\=\frac{-90\pm \sqrt{8100}}{-32}=\frac{-90\pm90}{-32}
\\
\\=\frac{-90+90}{-32}\text{ or }\frac{-90-90}{-32}=\frac{0}{32}\text{ or }\frac{-180}{-32}
\\
\\=0\text{ or }5.625$

0 is when the ball is first launched, 5.625 is when it hits the ground again.

4 0

2 years ago

Round 843 to the nearest ten.

alina1380 [7]

Hundreds Column:

8

Tens Column:

4

Ones Column:

3

The number 3 lies closer to 0, therefore the answer is <u>840</u>.

7 0

2 years ago

Work out 1 3/4 x 4 1/6

sattari [20]

Convert mixed number to improper fraction:

$1\dfrac{3}{4}=\dfrac{1\cdot4+3}{4}=\dfrac{4+3}{4}=\dfrac{7}{4}\\\\4\dfrac{1}{6}=\dfrac{4\cdot6+1}{6}=\dfrac{24+1}{6}=\dfrac{25}{6}\\\\1\dfrac{3}{4}\times4\dfrac{1}{6}=\dfrac{7}{4}\times\dfrac{25}{6}=\dfrac{7\times25}{4\times6}=\dfrac{175}{24}=\dfrac{168+7}{24}=7\dfrac{7}{24}$

8 0

3 years ago