We know that, in ∆ABC,
∠A+∠B+∠C = 180°
But the triangle is right angled at C
ie., ∠C = 90°
Therefore, ∠A+∠B+ 90° = 180°
⇒ ∠A + ∠B = 90°
Therefore, <u>cos(A + B) = cos 90º = 0</u>
Answer:
A. 125
Step-by-step explanation:
the sum of the remote angles is equal to the exterior angle
90+35=125
answers
1) 70
2) 3,840
3) 24
4) 72
<u>Explanation</u>
Q1
The surface area of a cone is given by;
S.A = 2Πrl + Πr²
Where r is the radius of the base and l is the lateral height.
Πr² = area of the base = 20 in²
2Πrl = Area of the lateral surface
= 2.5 × 20
= 50
Area of the cone = 50 + 20
= 70 in²
Q2
The sides of the Pythagorean triangle with legs of 12 and 16.
The 3rd side will be;
c = √(12² + 16²)
= √400 = 20
Volume = 12 × 16 × 20
= 3,840
Q3
The volume of a cone is given by;
volume = 1/3 Π r² h
This shows that the volume of a cone is a third the volume of the cylinder.
∴ Volume of the cylinder = 12 × 3
= 24 ft³
Q4
The volume of any regular figure is;
Volume = base area × height
When the dimensions area usually 3. Let these dimensions be x, y and z.
∴ volume = x × y × z = 9
Doubling the dimensions;
Volume = 2x × 2y × 2z = 2 × 2 × 2 × 9
= 8 × xyz = 8 × 9
= 72 ft²
R=x(A+B)
divide both sides by x
R/x=A+B
minus B both sides
(R/x)-B=A
A=(R/x)-B
