Generic Rectangle Calculator

Generic Rectangle Calculator

Visualize the distributive property with an area model for (a + b) x (c + d).

Last updated: June 2026 | By Patchworkr Team

Interactive Calculator

Enter four values to see how the distributive property breaks a rectangle into four parts.

Area Model Visualization
c = 4
d = 5
a = 2
8
10
b = 3
12
15
Area Breakdown
a x c
8
a x d
10
b x c
12
b x d
15
Total Area
45
(2 + 3) x (4 + 5) = 5 x 9 = 45

What the model shows

The rectangle is split into four regions that correspond to a x c, a x d, b x c, and b x d.

Why it matters

This geometric picture is the reason the distributive property works for binomial multiplication.

Formula and example

(a + b) x (c + d) = ac + ad + bc + bd

Example: (3 + 2) x (5 + 1) = 30.

Worked Example

Find (3 + 2) x (5 + 1).

1. a = 3, b = 2, c = 5, d = 1

2. ac = 15, ad = 3, bc = 10, bd = 2

3. Sum = 15 + 3 + 10 + 2

Final answer: 30

Frequently Asked Questions

Can I use negative numbers?

Yes. The model still works because multiplication distributes over signed values.

Can I use decimals?

Yes. The areas will be decimal values, and the total still matches the expanded product.

Why is this useful for algebra?

It shows why multiplying binomials produces four terms instead of two.

Does this only work for positive dimensions?

No. The calculator is a general algebraic model, not a physical rectangle tool.

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