Answer: The speed is 105 miles/ hr and the direction of the train would be East if the girl is the frame of reference.
Step-by-step explanation:
Since we have given that
Speed of train = 100 miles per hour
Speed of girl = 5 miles per hour
Since the girl is moving towards the back of train.
So,it means train and girl are moving in opposite direction.
So, Relative speed would be

Hence, the speed is 105 miles/ hr and the direction of the train would be East if the girl is the frame of reference.
Answer:
a2+b2=c2
Step-by-step explanation:
A right triangle is a triangle in which one of the angles is a 90∘ angle. A triangle can be determined to be a right triangle if the side lengths are known. If the lengths satisfy the Pythagorean Theorem (a2+b2=c2) then it is a right triangle.
Here we are given the three sides of the triangle.
So we have Heron's formula to find its area.
Heron's formula is given by :

where A, B and C are sides of triangle and S is semi perimeter which is given by,

plugging values of A, B and C to find S

S=13.5
Now plugging values of A, B , C and S in Heron's formula

A=26.14 mm²
Answer: Area of triangle is 26.14 mm².
Answer:
48 cm²
Step-by-step explanation:
The copper part is two equal triangles, find a triangle's area by counting squares and multiply by two.
Total copper=(Triangle area)(2)
=b(h)(½)(2)
=b(h)
=(6)(8)
=48 cm²
Answer:
- 57
Step-by-step explanation:
The n th term of an arithmetic sequence is
= a + (n - 1)d
where a is the first term and d the common difference
Here a = 13 and d = - 2.5, thus
= 13 + (28 × - 2.5) = 13 - 70 = - 57