Let and be the vectors along the diagonal of a parallelogram having area . Let the angle between and be acute. and . If , then an angle between and is

Question

Let  and  be the vectors along the diagonal of a parallelogram having area . Let the angle between  and  be acute.  and . If , then an angle between  and  is

Canvas Classes · Accepted Answer

🧠 " are Diagonals" — Area =

Read the question.  are diagonals (not sides) of parallelogram with area .

Area of parallelogram from diagonals: , so .

The condition  gives . With acute angle: .

🗺️ Working It Out

.
, so .
.

Compute  and  where .

.

So .

⚡ The Smart Move

Two distinct parallelogram-area formulas to know:
- Sides : Area .
- Diagonals : Area .

Use the right one based on what the question gives. Here  are diagonals, so .

The identity  is shorthand for , fixing  (ac

More questions from this chapter

More questions from this chapter