10 + 15x + x + 10
= 16x + 20
The answer is 10.73 years.
Here, the formula we can use is :
(for the average)
Substitute the values mentioned in the question.
10.54 = (10.35 + Girls)/2
21.08 = 10.35 + Girls
Girls = 10.73 years
Answer:
The height of the triangle is 7cm and the base is 16cm
Step-by-step explanation:
First of all we have to know the formula to calculate area of a triangle
a = area = 56
b = base
h = heigth
a = (b * h)/2
we replace the known values and we make 2 equations
56cm² = (b * h)/2
b = h + 9cm
we replace b by (h + 9cm) in the first equation
56cm² = (h + 9cm * h)/2
56cm² * 2 = h² + 9h
0 = h² + 9h - 112cm²
we use bhaskara formula:
(-b (±) √
(b² - 4ac) ) / 2a
we replace with the known values
h = (-9 (±) √
(9² - 4*1*(-112) ) ) / 2*1
h = (-9 (±) √
(81 + 448) ) ) / 2
h = (-9 (±) √529) /2
h = (-9 (±) 23)/2
h1 = (-9 + 23) / 2
h1 = 14 / 2
h1 = 7
h2 = (-9 - 23) / 2
h2 = -32 / 2
h2 = -16
The height of the triangle is 7cm and the base is 16cm
