All categories

3 years ago

Please help!! How do you do number 1?

Mathematics

1 answer:

alisha [4.7K]3 years ago

6 0

Do a ratio tall over shadow. How tall is tree / shadow. How tall is person / shadow then cross multiply. X/7.5 =5/3. 37.5=3x. Divide by 3 answer 12.5

You might be interested in

Solve using quadratic formula for 2x^(2)-10x+5=0

sergij07 [2.7K]

Answer:

$x=\frac{5+\sqrt{15}}{2},\:x=\frac{5-\sqrt{15}}{2}$

Step-by-step explanation:

$\mathrm{For\:a\:quadratic\:equation\:of\:the\:form\:}ax^2+bx+c=0\mathrm{\:the\:solutions\:are\:}$

$x_{1,\:2}=\frac{-b\pm \sqrt{b^2-4ac}}{2a}$

$\mathrm{For\:}\quad a=2,\:b=-10,\:c=5$

$x_{1,\:2}=\frac{-\left(-10\right)\pm \sqrt{\left(-10\right)^2-4\cdot \:2\cdot \:5}}{2\cdot \:2}$

$\sqrt{\left(-10\right)^2-4\cdot \:2\cdot \:5}$

Apply exponent rule: (-a)^n=a^n, if n is even

$\left(-10\right)^2=10^2$

$=\sqrt{10^2-4\cdot \:2\cdot \:5}$

$\mathrm{Multiply\:the\:numbers:}\:4\cdot \:2\cdot \:5=40$

$=\sqrt{10^2-40}$

$10^2=100$

$=\sqrt{100-40}$

$\mathrm{Subtract\:the\:numbers:}\:100-40=60$

$=\sqrt{60}$

$60\:\mathrm{divides\:by}\:2\quad \:60=30\cdot \:2$

$=2\cdot \:30$

$30\:\mathrm{divides\:by}\:2\quad \:30=15\cdot \:2$

$=2\cdot \:2\cdot \:15$

$15\:\mathrm{divides\:by}\:3\quad \:15=5\cdot \:3$

$=2\cdot \:2\cdot \:3\cdot \:5$

$2,\:3,\:5\mathrm{\:are\:all\:prime\:numbers,\:therefore\:no\:further\:factorization\:is\:possible}$

$=2\cdot \:2\cdot \:3\cdot \:5$

$=2^2\cdot \:3\cdot \:5$

$=\sqrt{2^2\cdot \:3\cdot \:5}$

Apply Radical Rule:

$=\sqrt{2^2}\sqrt{3\cdot \:5}$

Apply Radical Rule:

$\sqrt{2^2}=2$

$=2\sqrt{3\cdot \:5}$

$\mathrm{Refine}$

$=2\sqrt{15}$

$x_{1,\:2}=\frac{-\left(-10\right)\pm \:2\sqrt{15}}{2\cdot \:2}$

$\mathrm{Separate\:the\:solutions}$

$x_1=\frac{-\left(-10\right)+2\sqrt{15}}{2\cdot \:2},\:x_2=\frac{-\left(-10\right)-2\sqrt{15}}{2\cdot \:2}$

$\frac{-\left(-10\right)+2\sqrt{15}}{2\cdot \:2}$

Apply Rule -(-a)=a

$=\frac{10+2\sqrt{15}}{2\cdot \:2}$

$\mathrm{Multiply\:the\:numbers:}\:2\cdot \:2=4$

$=\frac{10+2\sqrt{15}}{4}$

$=\frac{2\left(5+\sqrt{15}\right)}{4}$

$\mathrm{Cancel\:the\:common\:factor:}\:2$

$=\frac{5+\sqrt{15}}{2}$

$\frac{-\left(-10\right)-2\sqrt{15}}{2\cdot \:2}$

$=\frac{10-2\sqrt{15}}{2\cdot \:2}$

$\mathrm{Multiply\:the\:numbers:}\:2\cdot \:2=4$

$=\frac{10-2\sqrt{15}}{4}$

$=\frac{2\left(5-\sqrt{15}\right)}{4}$

$\mathrm{Cancel\:the\:common\:factor:}\:2$

$=\frac{5-\sqrt{15}}{2}$

$\mathrm{The\:solutions\:to\:the\:quadratic\:equation\:are:}$

$x=\frac{5+\sqrt{15}}{2},\:x=\frac{5-\sqrt{15}}{2}$

8 0

2 years ago

The question is

Olin [163]

To estimate round each number to the closest whole number

7.8 would round to 8

307 would round to 300

8 x 300 = 2400

The answer would be c 2400

4 0

3 years ago

Read 2 more answers

At noon, the minute and the hour hands of a clock overlap. In how long will they again overlap?

stich3 [128]

Answer:

1 hour and 5 minutes

Step-by-step explanation:

8 0

3 years ago

Can someone please solve this problem for me

notsponge [240]

Answer:

D. 28.54

Step-by-step explanation:

To find the area of the shaded region, find the area of the circle and divide it in 4. This will the area of the portion with the triangle.

Now, find the area of the triangle and subtract the two. The resulting value will be the area of the shaded region.

Circle:

$A = \pi r^2\\A = \pi 10^2\\A = 100 \pi\\A = 314$

Divide by 4 for the area of the section with the triangle.

314/4 = 78.5

Triangle:

$A = \frac{1}{2}bh\\A = 0.5 (10 )(10)\\A=0.5(100)\\A=50$

Subtract the two, 78.5 - 50 = 28.5.

7 0

3 years ago

Write an equation in slope-intercept form that goes through (12, 4) and (20,8).

spayn [35]

Answer:

Equation in slope-intercept form that goes through (12, 4) and (20,8) is: $y = \frac{1}{2}x-2$

Step-by-step explanation:

Given two points are:

$(x_1,y_1) = (12,4)\\(x_2,y_2) = (20,8)$

Slope intercept form of line is given as:

$y = mx+b$

Here m is the slope of the line and b is the y-intercept.

Slope of a line is calculated by the formula:

$m = \frac{y_2-y_1}{x_2-x_1}$

Putting the values

$m = \frac{8-4}{20-12}\\m = \frac{4}{8}\\m=\frac{1}{2}$

Putting the value of slope in slope-intercept form we get

$y = \frac{1}{2}x+b$

To find the value of b, any one point will be put in the equation

Putting the first point (12,4) in the equation

$4 = \frac{1}{2}(12) + b\\4 = 6+b\\b = 4-6\\b = -2$

Putting the value of b

$y = \frac{1}{2}x-2$

Hence,

Equation in slope-intercept form that goes through (12, 4) and (20,8) is: $y = \frac{1}{2}x-2$

4 0

3 years ago