In class 9A the ratio of boys to girls is 3:4. if there are 12 boys,how many girls are there?
1 answer:
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Answer:
(1.13, 7.74) and (-4.13, 18.26)
Step-by-step explanation:
This can be solved in two ways: mathematically and graphically.
<u>Graphing</u>
Plot both lines and find where they intersect. See the attachment.
The intersection points are (1.13, 7.74) and (-4.13, 18.26)
<u>Mathematical</u>
y + 2x = 10
y = 10 - 2x
y = 3x² + 7x - 4
10 - 2x = 3x² + 7x - 4
3x² + 9x - 14 = 0
Solve this using the quadratic equation:
x = 1.13 and -4.13
Use these two values of x to find y:
y = 10 - 2x
y = 10 - 2(1.13)
y = 7.74
y = 10 -2x
y = 10 -2(-4.13)
y = 18.26
The two points are:
(1.13, 7.74) and (-4.13, 18.26)
Answer:
<em>The area of the trapezium is 168</em>
Step-by-step explanation:
<u>Area of a Trapezoid</u>
Given a trapezoid of parallel bases b1 and b2, and height h, the area is calculated with the formula:
The trapezoid in the figure has b1=15 and b2=27. We need to find the height. If we focus on triangle BCD, we can calculate the height as the distance EC by using the Pythagora's Theorem:
The side BC can be found as half the difference of the bases:
Solving for EC:
Now we have the height, calculate the area:
A = 168
The area of the trapezium is 168