Explanation

Given sinθ = 3/5, 1st quadrant

Use identity: sin²θ + cos²θ = 1

(3/5)² + cos²θ = 1  

9/25 + cos²θ = 1  

cos²θ = 1 - 9/25 = 16/25  

cosθ = ±4/5

In 1st quadrant both sin and cos are positive.  

So cosθ = 4/5.

Last verified on 04-05-2026

Explanation

• Mitochondria are called the powerhouse of the cell.
• Because they produce Adenosine Triphosphate (ATP).
• ATP is the energy currency of the cell.
• ATP provides energy for different cellular activities such as movement, growth, and transport.
• Energy is produced through aerobic cellular respiration using oxygen and الغذائی molecules.
• They are found in the cytoplasm of most eukaryotic cells.
• Richard Altmann first described mitochondria in 1890.

Main Parts of a Cell:

1. Cell membrane → Outer protective layer
2. Nucleus → Controls cell activities
3. Cytoplasm → Jelly-like material between membrane and nucleus

Last verified on 09-05-2026

Explanation

• Stack is used for recursion.
• Because it stores function calls in LIFO order during execution.
• Recursion works by repeatedly calling the same function.
• Each call is stored in memory until it completes execution.

Last verified on 08-06-2026

Explanation

• Pakistan is located at a key crossroads of Asia.
• It connects South Asia, Central Asia, and the Middle East.
• This strategic location increases its political and economic importance.
• It also plays a key role in trade and regional connectivity.
• Major routes and projects pass through Pakistan.

Last verified on 25-05-2026

Explanation

• An electric generator is a device that converts mechanical energy into usable electrical energy.
• This process is based on the principle of electromagnetic induction.
• Discovered in 1831 by British scientist Michael Faraday.

Last verified on 27-04-2026

Explanation

• Silica (SiO₂) is the main component of glass.
• It providing its transparency and hardness.
• It forms a network structure when melted, giving glass its solid yet brittle nature.

Last verified on 07-06-2026

Explanation

• “At the eleventh hour” means at the very last moment.
• It refers to doing something just before it is too late.
• Example: He submitted the form at the eleventh hour.

Last verified on 14-05-2026

Explanation

Area of a triangle = 1/2 _ base _ height

Let old base = B, old height = H.  

Old area = 1/2 _ B _ H

New base = B + 25% of B = B + 0.25B = 1.25B  

New height = H - 20% of H = H - 0.20H = 0.80H

New area = 1/2 _ 1.25B _ 0.80H  

= 1/2 _ 1.00 _ B _ H  

= 1/2 _ B * H

New area = old area. It stays the same.

Last verified on 25-05-2026

Explanation

Put a = 1 into a² + b² = 170.

1² + b² = 170  

1 + b² = 170  

b² = 170 - 1  

b² = 169  

b = 13 or b = -13

So b equals 13 or -13.

Last verified on 25-05-2026

Explanation

A triangle is classified based on its angles.

If one angle is 90°, it is a right-angled triangle.

The given triangle has angles 30°, 60°, and 90°.

Since it contains a 90° angle, it is a right triangle.

Last verified on 25-05-2026